LIBRARY 


UNIVERSITY  OF  CALIFORNIA. 


Class 


m 


WORKS  OF 
Dr.   GEORGE   P.   MERRILL 


PUBLISHED   BY 


JOHN  WILEY  &  SONS. 


Stones  for  Building  and  Decoration. 

Third  Edition,  Revised  and  Enlarged.  8vo,  x  4-  557 
pages,  one  double-page  and  32  full-page  plates,  and 
24  figures  in  text.  Cloth,  $5.00. 

The  Non-metallic  Minerals. 

Their  Occurrence  and  Uses.  Second  Editi6n< 
Revised  and  Enlarged,  8vo,  xii  +  432  pages, 
38  full-page  plates,  mostly  half-tones,  and  55 
figures  in  the  text.  Cloth,  $4.00. 


PLATE     I. 

Views  in  Graphite  Mine  near  Hague,  Warren  County,  New  York. 
[From  photograph  by  C.  D.  Walcott.] 

[Frontispiece.] 


THE 

NON-METALLIC    MINERALS. 

THEIR  OCCURRENCE  AND  USES. 


BY 

GEORGE    P.   MERRILL, 

Head  Curator  of  Geology  in  the  U.  S.  National  Museum,  and 

Professor  of  Geology  in  the  George  Washington  (formerly  Columbian)  University, 

Washington,  D.  C.;  Author  of  "  Stones  for  Building  and  Decoration," 

"  Rocks,  Rock-weathering,  and  Soils,"  "  Contributions  to  a 

History  of  American  Geology,"  etc. 


SECOND  EDITION,    REVISED 

FIRST    THOUSAND 


NEW  YORK: 
JOHN  WILEY  &  SONS. 

LONDON:  CHAPMAN  &  HALL,  LIMITED. 

1910 


V\5 


Copyright,  1904.  1910- 

BY 
GEORGE  P.  MERRILL 


THE  SCIENTIFIC   PRESS 

BOBF.RT   ORUMMOND  AND   COMPANY 

BROOKLYN.   N.   Y. 


PREFACE  TO   THE   SECOND  EDITION. 


THE  first  edition  of  this  work  was  little  more  than  a  reprint 
of  a  handbook  of  the  collections  in  Applied  Geology  in  the 
U.  S.  National  Museum.  An  attempt  was  there  made,  for  the  first 
time  in  America,  to  bring  together  widely  scattered  notes  relating 
to  many  of  the  minor  and  little  used  minerals,  it  being  felt  that  with 
the  rapid  development  of  the  arts  the  time  had  come  for  a  review, 
at  least,  of  this  branch  of  the  mining  industry,  as  well  as  a  look  into 
future  possibilities,  so  far  as  the  development  of  natural  resources 
would  permit.  Since  the  work  was  written,  much  has  been  accom- 
plished in  the  way  of  both  study  and  exploitation,  as  will  be  evident 
to  one  who  will  peruse  the  voluminous  publications  of  the  U.  S. 
Geological  Survey  and  the  columns  of  the  trade  and  mining  journals, 
and  it  is  felt  that  the  time  has  now  arrived  for  putting  the  matter 
in  a  form  more  concise  as  well  as  more  comprehensive.  In  doing 
this,  the  author  has  availed  himself  of  the  great  mass  of  literature 
passing  through  his  hands  as  Head  Curator  of  the  Department  of 
Geology,  as  well  as  an  experience  of  near  thirty  years  in  collecting, 
observing  and  arranging  the  materials  under  his  care.  He  has 
drawn  for  information  upon  every  available  source,  and  has  striven 
to  give  full  credit  therefor. 

The  name  Non-Metallic,  as  used,  it  may  be  well  to  state,  relates 
to  the  uses  to  which  the  various  substances  are  put  rather  than  to 
their  true  mineral  nature.  Otherwise  expressed,  the  materials  here 
described  are  considered  with  reference  to  their  uses  other  than  as 
sources  of  metals.  In  several  instances,  it  is  evident,  the  same  mate- 
rial may  be  utilized  for  its  metallic  constituents  as  well,  as  is  the  case 


236416 


iv  PREFACE. 

with  the  manganese  oxides,  but  in  such  cases  this  phase  of  the  sub- 
ject is  touched  upon  but  lightly. 

It  should  scarcely  be  necessary  to  state  that  in  several  instances, 
as  those  of  cements,  coals,  phosphate,  etc.,  the  subject  matter  is  so 
comprehensive  that  each  might  well  demand  a  volume  by  itself. 
In  these  cases,  summaries  only  are  attempted  and  reference  made  to 
authentic  treatises  in  the  accompanying  bibliographies. 


TABLE  OF  CONTENTS  AND  SCHEME  OF 
CLASSIFICATION. 


I.  The  Elements:  PAGE 

i.  Carbon i 

Diamond i 

Graphite 6 

2.  Sulphur 14 

3.  Arsenic 22 

II.  Sulphides  and  arsenides: 

i.  Realgar  and  orpiment  ;    auripigment 23 

: ,.  Cobalt  minerals 25 

Cobaltite 25 

Smaltite 26 

Skutterudite 27 

Gla,ucodot 27 

Linmeite 27 

Sychnodymite 28 

Erythrite  or  cobalt  bloom 28 

Asbolite 28 

3.  Arsenopyrite;  mispickel  or  arsenical  pyrites 30 

4.  Lollingite;  leucopyrite 31 

5.  Pyrites 32 

6.  Pyrrhotite 38 

7.  Molybdenite 39 

8.  Patronite ;  vanadium  sulphide 41 

III.  Halides: 

1.  Halite;  sodium  chloride;  or  common  salt 43 

2.  Fluorite 63 

3.  Cryolite 65 

IV.  Oxides: 

1.  Silica 67 

Quartz 67 

Flint 68 

Buhrstone 68 

Tripoli 69 

Diatomaceous  earth 70 

2.  Corundum  and  emery 73 

v 


vi          TABLE  OF  CONTENTS  AND  SCHEME   OF  CLASSIFICATION. 

IV.  Oxides — Continued:  PAGE 

3.  Bauxite 89 

4.  Diaspore 103 

5.  Gibbsite;  hydrargillite 103 

6.  Ocher ;  mineral  paint 104 

7.  Ilmenite;  menaccanite,   or  titanic  iron 112 

8.  Rutile 113 

9.  Chromite;  chrome  iron  ore 114 

10.  Manganese  oxides 121 

Franklinite 122 

Hausmannite 122 

Braunite 122 

Polianite , 123 

Pyrolusite 123 

Manganite 123 

Psilomelane 123 

Wad  or  bog  manganese 124 

11.  Mineral  waters 131 

V.  Carbonates: 

1.  Calcium  carbonate 135 

Calcite;  calc  spar;  Iceland  spar 135 

Limestones 138 

Portland  cement 141 

Roman  cement 144 

Chalk 145 

Playing  marbles 146 

Lithographic  limestones 147 

2.  Dolomite 152 

3.  Magnesite ; 153 

4.  Witherite 157 

5.  Strontianite 158 

6.  Rhodochrosite;  diallogite ... 159 

7.  Natron 159 

8.  Trona;  urao 159 

VI.  Silicates: 

1.  Feldspars 161 

2.  Micas - 164 

3.  Asbestos 183 

4.  Garnet 197 

5.  Zircon 199 

6.  Spodumene  and  petalite 200 

7.  Lazurite;  lapis  lazuli;  native  ultramarine 202 

8.  Allanite;  orthite 204 

9.  Gadolinite 205 

10.  Cerite 207 

11.  Rhodonite 207 

12.  Steatite;  talc  and  soapstone 208 

13.  Pyrophyllite;  agalmatolite  and  pinite- 216 


TABLE  OF  CONTENTS  AND  SCHEME  OF  CLASSIFICATION,  vii 

IV.  Silicates — Continued:  PAGE 

14.  Sepiolite;  meerschaum 218 

15.  Clays 221 

16.  Fuller's-earth 252 

VII.  Niobates,  tantalates,  and  tungstates: 

1.  Columbite  and  tantalite 255 

2.  Yttrotantalite 255 

3.  Samarskite 256 

4.  Wolframite,  Hiibnerite  and  Ferberite 257 

5.  Scheelite 263 

VIII.  Phosphates  and  vanadates: 

1.  Apatite;  rock  phosphates;  guano,  etc 266 

2.  Monazite 303 

3.  Torbernite ' 307 

4.  Wavellite 308 

5.  Amblygonite 309 

6.  Triphylite  and  lithiophilite 310 

7.  Vanadinite 311 

8.  Descloizite 312 

XI.  Nitrates: 

1.  Niter,  potassium  nitrate 315 

2.  Soda  niter 315 

3.  Nitro-calcite 318 

X.  Borates: 

1.  Borax  or  tincal;  borate  of  soda 322 

2.  Ulexite ;  boronatrocalcite 3  22 

3.  Colemanite;  Priceite 322 

4.  Boracite  or  stassfurtite;  borate  of  magnesia 322 

XI.  Uranates: 

1.  Uraninite ;  pitchblende 330 

2.  Carnotite 332 

XII.  Sulphates: 

1.  Barite;  heavy  spar 334 

2.  Gypsum 33  7 

3.  Celestite 343 

4.  Mirabilite;  Glauber  salt 344 

5.  Glauberite ' 347 

6.  Thenardite 348 

7.  Epsomite ;  epsom  salts 348 

8.  Polyhalite;  'kainite  and  kieserite 349 

9.  Alums: 

Kalinite 350 

Tschermigite 350 

Mendozite 351 

Pickeringite 351 

Halotrichite 351 

Apjonite 351 

Alunnogen 352 


viii        TABLE  OF  CONTENTS  AND  SCHEME  OF  CLASSIFICATION. 

XII.  Sulphates — Continued:  PAGE 

Aluminite 355 

Alunite 35  5 

Alum  slate  or  shale 357 

XIII.  Hydrocarbon  compounds: 

1.  Coal  series 359 

Peat 360 

Lignite  or  brown  coal 362 

Bitumionus  coal 363 

Torbanite 363 

Anthracite  coal 364 

2.  Bitumen  series 367 

Marsh  gas;  natural  gas 372 

Petroleum 373 

Asphaltum;  mineral  pitch 3 75 

Manjak 381 

Elaterite;  mineral  caoutchouc 382 

Wurtzillite 382 

Albertite 383 

Grahamite 384 

Carbonite  or  natural  coke 385 

Uintaite ;  gilsonite 386 

3.  Ozokerite;  mineral  wax;  native  paraffin 388 

4.  Resins 391 

Succinite;  amber 391 

Retinite 393 

Chemawinite 393 

Gum  copal 394 

XIV.  Miscellaneous: 

1.  Grindstones;   whetstones  and  hones 400 

2.  Millstones 409 

3.  Pumice 410 

4.  Rottenstone 412 

5.  Madstones 413 

6.  Molding  sand 413 

7.  Sand  for  mortars  and  cements 418 

8.  Sand  for  glass  making 419 

9.  Glauconitic  sand 420 

to.  Road-making  materials 421 


LIST   OF   ILLUSTRATIONS. 


PLATES. 

PACING    PAGE 

I.  Views    in    Graphite  Mine,    near  Hague,    Warren   Co.,    N.    Y.      From 

photograph  by  C.  D.  Walcott Frontispiece 

II.  Section  of  Salt  Beds  at  Stassfurt,  Germany.     Trans.  Edinburgh  Geo- 
logical Society.     Vol.  V,  1884 56 

III.  Tripoli  Mine,  Seneca,  Mo.     From  a  photograph 70 

IV.  Bed  of  Diatom   Earth,  Great  Bend  of  Pitt  River,  Shasta  Co.,  Cal.     From 

photograph  by  J.  S.  Diller,  U.  S.  Geol.  Survey 72 

V.  Vein  between  Peridotite  and  Gneiss,  Corundum  Hill,  Macon  Co.,  N.  C. 

After  J.  H.  Pratt,  Bull.  No.  180,  U.  S.  Geol.  Survey : 76 

VI.  Fig.  i,  Corundum  Vein  at  Laurel  Creek,  Ga.     After  J.  H.  Pratt,  Bull. 

No.  180,  U.  S.  Geol.  Survey 78 

Fig.  2,  Bauxite  Bed,  Saline  Co.,  Ark.     From  photograph  by  C.  W.  Hayes, 

U.  S.  Geol.  Survey 78 

VII.  Microstructure  of   Emery.     After   Tschermak,    Min.   u.   Pet.   Mittheil., 

XIV,  Part  IV 82 

VIII.  Church  Bauxite  Bank,  showing  Method  of  Mining.     From  a  photograph 

by  C.  W.  Hayes,  U.  S.  Geol.  Survey 94 

IX.  Fig.  i,  Segregation  Veins  of  Chrome  Iron,  near  Rustenburg,  South  Africa. 

From  Trans.  Geol.  Soc.  of  South  Africa 116 

Fig.  2,  Open  Cut  Manganese  Mine,  Crimora,  Virginia.    After  Thos.  Wat- 
son, Mineral  Resources  of  Virginia 1 16 

X.  Botryoidal  Psilomelane,  Crimora,  Virginia 124 

XL  Ideal  Sections  to  Show  Origin  of  Manganese  through  Weathering  of 
Limestone.     After  Penrose,  Ann.  Rep.  Geol.  Survey  of  Arkansas, 

Vol.  I,  1890 126 

XII.  Views  Showing  Occurrence  of  Calcite  in  Iceland.     After  Thorroddsen. . .    136 

XIII.  Fig.  i,  Limestone  Quarry,  Rockland,  Me.     From  photograph  by  E.  S. 

Bastin,  U.  S.  Geol.  Survey 138 

Fig.  2,  Limestone  Quarry,  Oglesby,  111.     From  a  photograph  by  E.  C. 

Eckel,  U.  S.  Geol.  Survey 138 

XIV.  Cement  Quarry,  near  Whitehall,  Ulster  Co.,  N.  Y.     From  photograph 

by  N.  H.  Darton,  U.  S.  Geol.  Survey 144 

ix 


x  LIST   OF  ILLUSTRATIONS. 

FACING    PAGE 

XV.  Fig.   i,    Quarry    of    Lithographic    Limestone,    Solenhofen,  Bavaria. 

From  a  photograph 1^4 

Fig.  2,  Stockwork  of  Magnesite  Veins  in  Serpentine,  near  Winchester, 
Riverside   Co.,  Cal.     After  F.  L.  Hess,  Bull.  No.  355,    U.    S. 

Geol.  Survey !^4 

XVI.  Fig.  i,  Magnesite  Outcrop,  Hixon  Ranch,  Mendocino  Co.,  Cal.     Ibid.  156 

Fig.  2,  Sonoma  Magnesite  Mine,  near  Cazadero,  Cal.     Ibid 156 

XVII.  Fig.   i,  Feldspar  Quarry,  Topsham,  Me.      From  photograph  by  E. 

S.  Bastin,  U.  S.  Geol.  Survey 162 

Fig.  2,  Feldspar  Quarry,  South  Glastonbury,  Conn.     Ibid 162 

XVIII.  Fig.  i,  Large    Spodumene    Crystals    in   Granitic  Rock,  Etta  Mine, 

Black  Hills,  S.  D.     From  photograph  by  E.  O.  Hovey 200 

Fig.  2,   Soapstone  Quarry,  Nelson  Co.,  Va.     After  Thos.  Watson, 

Mineral  Resources  of  Virginia ; 200 

XIX.  Soapstone  Quarry,  Lafayette,  Pennsylvania 214 

XX.   Kaolin  Pit,  Delaware  Co.,  Pennsylvania 220 

XXI.  Fig.    i,   Kaolinite,   and    Fig.    2,    Washed  Kaolin   as  Seen  under  the 

Microscope 2  28 

XXII.  Fig.  i,  Halloysite,  and  Fig.  2,  Glacial  (Leda^  Clay,  as  Seen  under  the 

Microscope 230 

XXIII.  Bed  of  Glacial  (Leda)  Clay,  Lewiston,  Me.,  from  photograph  by  L.  H. 

Merrill 23  2 

XXIV.  Fig.  i,  Fuller's  Earth  Pits,  Quincy,  Fla.     After  H.  Ries,  Clays,  Their 

Properties  and  Uses;    Fig.  2,  Phosphate  Pit,  Florida 252 

XXV.  Fig.  i,  Clay,  Albany,  Wyo.,  and  Fig.  2,  Fullers'  Earth,  as  Seen  under 

the  Microscope 254 

XXVI.  Map  of  the  Florida  Phosphate  Regions,  after  G.  H.  Eldridge,  U.  S. 

Geol.  Survey. 278 

XXVII.  Sections  through  the  Tennessee  Phosphate  Beds.     After  C.  W.  Hayes, 

U.  S.  Geol.  Survey 282 

XXVIII.  Phosphate  Mine,  Mt.  Pleasant,  Tenn.     Showing  Area  Stripped,  and 
Method  of  Mining.     From  photograph  by  C.  W.  Hayes,  U.  S. 

Geol.  Survey 284 

XXIX.  Monazite  Mining,   Gaffney,   S.   C.     From  photograph  by   Douglas 

Sterrett,  U.  S.  Geol.  Survey 304 

XXX.  Borax  Mine,  near  Daggett,  Cal.     Interior  and  Exterior  View*.     From 

photographs 326 

XXXI.  Gypsum   Quarry,   Fort   Dodge,   Iowa.     From  photograph   by   Iowa 

Geol.  Survey ' 338 

XXXII.  Map  Showing  Developed  Coal  Fields  in  the  United  States.     From 

Rep.  of  Eleventh  Census 360 

XXXIII.  Fig.    i,  Typical  Moss  or  Peat  Bog,  near  Augusta,  Me.     After  E.  S. 

Bastin,  Bull.  376,   U.  S.  Geol.  Survey;  Fig.  2,  Section  of  a  Peat 
Bog,  near  Mias,  Russia.     From  a  photograph  by  A.  M.  Miller..   362 

XXXIV.  Fig.   i,  Quarry   in   Bituminous   Sandstone,  Oklahoma.     After  G.  H. 

Eldridge,  U.  S.  Geol.  Survey;  Fig.  2,  Ditto,  Santa  Cruz  District, 
California 364 


LIST   OF  ILLUSTRATIONS.  xi 

FACING    PAGE 

XXXV.  Microstructure  of   Mica  Schist  Used  in  Making  Hones;    Fig.  i  cut 

across  the  grain;    Fig.  2,  cut  parallel  with  grain 404 

XXXVI.  Fig.   i,   Quarry  in  Mica  Schist  used  in  making  Whetstones,   Pike 
Manufacturing    Co.;  Fig.  2,   Quarry  in  Novuculile,    Arkansas, 

Pike  Manufacturing  Co 406 

XXXVII.  Microstructure  of  (i)  Arkansas  Novaculite,  and  (2)  Ratisbon  Razor 

Hone.     The  dark  bodies  in  (2)  are  Garnets 408 

XXXVIII.  Fig.  i,  Bed  of  Pumice  Dust,  Kansas.     From  a  photograph;    Fig.  2, 

Quarry  of  Quartz  Sand,  Ottawa,  111.     From  a  photograph 410 


FIGURES  IN  TEXT 

PAGE 

1.  Diamond  Crystals.     Ann.  Rep.  U.  S.  National  Museum,  1903 2 

2.  Section  of  Kimberley  Mines,  S.  Africa.     After  Rennert 3 

3.  Largest  Known  Black  Diamond.     After  Kunz,  Min.  Resources  of  the  United 

States,  1902 4 

4.  Block  of  Limestone  with  Alternating  Layers  of  Sulphur.     From  Ann.  Rep. 

U.  S.  National  Museum,  1899 20 

5.  Plan  of  Pyrite  Lens,  Louisa  Co.,  Va.     After  Thos.  Watson,  Mineral  Re- 

sources of  Virginia 34 

6.  Section  Showing  Stringers  of  Pyrite  Interleaved  with  Schist.     Ibid 35 

7.  Map  of  La  Quimica  Patronite  Area,  Minasragra,  Peru.     After  D.  F.  Hewett, 

Bull.  Am.  Inst.  Min.  Eng.,  1909 42 

8.  Crystals  of    Halite,  Stassfurt,  Germany.     From  Ann.  Rep.   U.  S.  National 

Museum,  1899 45 

9.  Map  of  Petite  Anse,  Louisiana.     After   Hilgard 51 

10.  Section  of  Petite  Anse,  La.     Ibid 52 

11.  Crystals  of  Sylvite.     From  Ann.  Rep.  U.  5.  National  Museum,  1899 54 

12.  Section  of  Fluorite  Vein,  Chittenden  Co.,  Ky.     After  W.  S.  T.  Smith,  Prof. 

Papers,  U.  S.  Geol.  Survey,  No.  36 64 

13.  Corundum  Crystals.     From  Ann.  Rep.  U.  S.  National  Museum,  1906 73 

14.  Ideal  Section  of  Corundum  Contact,    Corundum   Hill,    Macon    Co.,    N.    C. 

After  J.  H.  Pratt,  Bull.  U.  S.  Geol.  Survey 75 

15.  Map  of  Corundum  Hill,  North  Carolina.     Ibid 76 

16.  Map  of  Buck  Creek  Peridolite  Area.     Ibid 77 

17.  Map  of  Laurel  Creek,  Ga.,  Peridotite  Area.     Ibid 78 

18.  Map  of  Corundum  Areas  of  Canada «.  80 

19.  Map  showing  Location  of  Emery  Deposit,  Chester,  Mass 85 

20.  Cross-section  of  Old  Emery  Mine,  Chester 86 

21.  Map  showing  Geological  Relation  of  Georgia  and  Alabama  Bauxite  Deposits. 

After  C.  W.  Hayes,  Ann.  Rep.  U.  S.  Geol.  Survey 98 

22.  Section  to  show  Residual  Nature  of  Bauxite  Deposit.     Ibid 99 

23.  Cross-section   of    Rutherford  and   Barclay  Paint  Mine,  Lehigh  Gap,  Penn. 

After  C.  E.  Hesse. 108 

24.  Ground  Plan  of  Crimora  Manganese  Deposits.     After  C.  E.  Hall 126 

25.  Sections  through  Crimora  I.Ianganese  Deposits.     Ibid 126 


xii  LIST  OF  ILLUSTRATIONS. 

PAGB 

26.  Section  of  Manganese  Deposit   near  Bahia,  Brazil.     After  Branner,  Trans. 

Am.  Inst.  Min.  Engs 128 

27.  Map   showing   Mica-producing   Areas  of   North   Carolina.     After   Douglas 

Sterrett,  Bull.  315,  U.  S.  Geol.  Survey,  1907 170 

28.  Sections  of  Mica  Veins,  Yancey  Co.,  N.  C.     After  W.  C.  Kerr,  Trans.  Am. 

Inst.  Min.  Engs.,  Vol.  8,  1880 171 

29.  Generalized  Section  of  Mica  Mine  near  Custer,  S.  D.     After  D.  Sterrett, 

Bull.  380,  U.  S.  Geol.  Survey 174 

30.  Section  through  Lake  Girard  Mica  Mine,   Quebec,  Canada.     After  Cirkel. 

Mica,  Occurrence,  Exploitation  and  Uses 175 

31.  Section  of  Vein  in  Baby  Mine,  North  Burgess,  Ontario.     Ibid 1 76 

32.  Mica-bearing  Pyroxene  Dike  in  Gneiss.     An  Illustration  of  Pocket  Deposit. 

After  Cirkel.     Ibid 177 

33.  Mica-bearing  Pyroxene  Dike  in  Limestone.     Ibid 178 

34.  Section  of  Asbestos- bearing  Rocks,  Thetford,  Canada.     After  Cirkel,  Asbestos, 

Its  Occurrence,  Exploitation  and  Uses 190 

35.  Map  Showing  Serpentine  Areas  in  Eastern  Township  of  Quebec.     Ibid 190 

36.  Vertical  Section  Wall  of  Asbestos  Pit,  Black  Lake,  Canada 191 

37.  Block  of    Serpentine  with  Vein  of   Asbestiform  Mineral.     From  Rep.  U.  S. 

National  Museum,  1899 192 

38.  Outlines  of  Garnet  Crystals 1 98 

39.  Outlines  of  Zircon  Crystals 200 

40.  Section  Showing  Apatite  Deposits  in  Wallingford  Mica  Mine.     After  Cirkel  .   270 

41.  Section  through  Apatite  and  Mica  Deposits,  Templeton,  Canada.     Ibid 274 

42.  Map  of  Tennessee  Phosphate  Region.     After  C.  W.  Hayes,  i7th  Ann.  Rep. 

U.  S.  Geol.  Survey 283 

43.  Section  Showing  Mode  of  Occurrence  and  Formation  of  Residual  Phosphates 

in  Tenn.     After  C.  W.  Hayes,  U.  S.  Geol.  Survey 286 

44.  Typical  Section,  Lower  Portion  of  Phosphate  Beds,  Montpelier,  Idaho.     After 

F.  B.  Weeks,  Bull.  315,  U.  S.  Geol.  Survey 288 

45.  Map  of  Monazite  Areas  in  the  Carolinas.     After  J.  H.  Pratt,  Trans.  Am. 

Inst.  Min.  Engrs 305 

46.  Outlines  of  Vanadinite  Crystals 314 

47.  Map  of  Chilean  Nitrate  Region.     After  Fuchs  and  De  Launey 318 

48.  Section  of  Tilted  Borate  Beds,  Furnace  Valley,  California.    After  C.  R.  Keyes, 

Bull.  Am.  Inst.  Min.  Engrs.,  1909 325 

49.  Sketch  Map  of  California  Borax  Localities.     Ibid 326 

50.  Ideal  Section  of  Bennett  Barite  Mine,  Pittsylvania  Co.,  Va.     After  Watson 

Mineral  Resources  of  Virginia 336 

51.  Sketch  Map  of  Gila  River  Alum  Deposit.     After  C.  W.  Hayes,  Bull.  315,  U. 

S.  Geol.  Survey 35  2 

52.  Section  Across  Bullah-Delah  Mountain,  Showing  Alunte  Beds.     After  Pitt- 

man,  Min.  Resources  N.  S.  Wales 356 

53.  Plan  of  Pitch  Lake,  Trinidad.     After  S.  F.  Peckham 376 

54.  Section  of  Asphalt  Vein  East  of  Havana,  Cuba.     After  R.  C.  Taylor 378 

55.  Section  through  Quarry  of  Gilson  Paving  Co.     After  G.  H.  Eldridge,  U.  S. 

Geol.  Survey 38° 


THE  NON-METALLIC   MINERALS, 

EXCLUSIVE  OF  GEMS,  BUILDING  STONES,  AND  MARBLES. 


I.  THE    ELEMENTS. 

I.    CARBON. 

THE  numerous  compounds  of  which  carbon  forms  the  chief 
constituent  are  widely  variable  in  their  physical  properties  and  origin. 
As  occurring  in  nature  few  of  its  members  possess  a  definite  chemical 
composition  such  as  would  constitute  a  true  mineral  species,  and 
they  must  for  the  most  part  be  looked  upon  as  indefinite  admixtures 
in  which  carbon,  hydrogen,  and  oxygen  play  the  more  important 
roles.  For  present  purposes  the  entire  group  may  be  best  con- 
sidered under  the  heads  of  (i)  The  Pure  Carbon  series;  (2)  The 
Coal  series,  and  (3)  The  Bitumen  series,  the  distinctions  being  based 
mainly  on  the  gradually  increasing  amounts  of  volatile  hydrocarbons, 
a  change  which  is  accompanied  by  a  variation  in  physical  condition 
from  the  hardest  of  known  minerals  through  plastic  and  liquid  to 
gaseous  forms.  Here  will  be  considered  only  the  members  of  the 
pure  carbon  series,  the  others  being  discussed  under  the  head  of 
hydrocarbon  compounds. 

Diamond. — This  mineral  crystallizes  in  the  isometric  system, 
with  a  tendency  toward  octahedral  forms,  the  crystals  showing  curved 
and  striated  surfaces.  (Fig.  i.)  The  hardness  is  great,  10  of  Dana's 
scale;  the  specific  gravity  varies  from  3.1  in  the  carbonados  to  3.5 
in  good  clear  crystals.  The  luster  is  adamantine;  the  colors,  white 
or  colorless,  through  yellow,  red,  orange,  green,  blue,  brown  to  black. 
The  transparent  and  highly  refractive  forms  are  of  value  as  gems, 


THE  NON-METALLIC  MINERALS. 


FlG.  i. — Diamond  crystals;  characteristic  forms. 
[U.  S.  National  Museum.] 


and  can  best  be  discussed  in  works  upon  this  subject.     We  have 

to  do  here  rather  with  the 
rough,  confused  crystal- 
line aggregates  or  round- 
ed forms,  translucent  to 
opaque,  which,  though 
of  no  value  as  gems,  are 
of  the  greatest  utility  in 
the  arts.  To  such  forms 
the  name  black  diamond, 
bort,  and  carbonado  are 
applied. 

Origin  and  occur- 
rence.—  The  origin  of 
the  diamond  has  long 
been  a  matter  of  dis- 
cussion. A  small  pro- 
portion of  the  diamonds 
of  the  world  are  found  in  alluvial  deposits  of  gravel  or  sand.  In 
the  South  African  fields  they  occur  in  a  so-called  blue  gravel,  formed, 
according  to  Lewis,  along  the  line  of  contact  between  an  eruptive 
rock  (peridotite)  and  highly  carbonaceous  shales.  They  were 
regarded  by  Lewis  as  originating  through  the  crystallization  of  the 
carbon  of  the  shales  by  the  heat  of  the  molten  rock.  De  Launay 
states,  however,  that  there  is  no  necessary  connection  between  the 
shales  and  the  diamond,  and  shows  with  apparent  conclusiveness 
that  the  latter  occur  often  in  a  broken  and  fragmental  condition, 
such  as  to  indicate  beyond  doubt  that  they  originated  at  greater 
depths  and  were  brought  upward  as  phenocrysts  in  the  molten 
magma  at  the  time  of  its  intrusion.  The  primary  origin  of  the 
diamonds  he  regards  as  through  the  crystallization,  under  great 
pressure,  of  the  carbon  contained  in  the  basic  magma  in  the  form 
of  metallic  carbides. 

The  diamond-bearing  rock,  i.e.,  the  true  parent  rock,  is  now  very 
generally  conceded  to  be  the  peridotite,  and  to  which  Lewis  gave 
the  name  kimberlite. 

The  Brazilian  diamonds  come  mainly  from  Minas  Geraes  and  the 


ELEMENTS.  3 

Paraguaca  district,  in  the  State  of  Bahia,  where  they  are  found  in 
detrital  material  resulting  from  the  breaking  down  of  sedimentary 
metamorphic  rocks.  These  rocks,  as  described  by  Branner,1 
belong  to  the  Lavral  series  of  Carboniferous  formations,  and  con- 
sist of  false-bedded  pinkish  red  sandstone,  conglomerate  and 
quartzite.  The  washings  yielding  the  diamonds  are  altogether 
along  streams  that  flow  over  these  beds  or  their  detrital  ma- 


SECTION  OF  KIMBERLEY  MINE 

LOOKING  EAST 

350  FEET       . 


FIG.  2. — Section  of  Kimberley  Diamond  Mines. 
[After  Rennert.] 


terials  and  there  is  apparently  no  doubt  that  they — and  the 
quartzite  in  particular — represent  the  parent  rock.  Cases  of 
finding  of  diamonds  in  the  quartzite  matrix  have  been  reported, 
but  apparently  need  authentication.  There  are  no  eruptive  rocks 
in  connection  with  the  beds  over  the  greater  part  of  this 
district,  and  the  diamonds,  so  far  as  yet  determined,  cannot 
be  attributed  to  an  igneous  origin,  Branner,  however,  notes 
the  existence  of  considerable  areas  of  serpentine  (altered  peri- 
dotite?)  underlying  the  sedimentary  series,  and  it  is  surmised  as 
possible  that  such  may  have  been  the  original  source  of  the 

1  Engineering  and  Mining  Journal,  LXXXVII,  1909,  p.  981. 


4  THE  NON-METALLIC  MINERALS. 

diamonds   themselves.     The  problem  cannot  be  considered  as  yet 
solved. 

According  to  Kunz,1  95  per  cent  of  all  diamonds  at  present 


FIG.  3. — Largest  Known  Black  Diamond.     Weight  3150  carats. 
[U.  S.  Geological  Survey.] 

obtained  come  from  the  Kimberly  Mines,  Griqua  Land,  west  South 
Africa;  of  these,  some  47  per  cent  are  bort.  The  remainder  come 
from  Brazil,  India,  and  Borneo.  A  few  have  been  found  in  North 
America,  the  Ural  Mountains,  and  New  South  Wales,  but  these 
countries  are  not  recognized  as  regular  and  constant  sources  of 
supply.  The  Australian  diamonds,  it  may  be  noted,  have  been  found 
in  igneous  rocks,  of  the  nature  of  diabase,  or  dolerite.2  Recently 


1  Gems  and  Precious  Stones,  New  York,  1890. 
2Geol.  Mag.,  Vol.  VI,  Nov.,  1909,  p.  492. 


ELEMENTS.  5 

diamonds  have  been  reported  from  near  Murfreesboro,  in  Pike 
County,  Arkansas,  associated  with  peridotites  under  much  the  same 
conditions  as  in  South  Africa. 

The  largest  known  gem  diamond  is  the  Cullinan,  found  in  1905 
in  the  Premier.  Mine,  Transvaal,  South  Africa.  This,  before  cutting, 
measured  roughly  4X2^X2  inches  and  weighed  3,024!  carats.  The 
largest  black  diamond,  or  carbon,  is  that  shown  approximately 
natural  size  in  Fig.  3.  This  was  found  in  the  Paraguaca  district 
of  Brazil  in  1895,  and  weighed  3,078  carats. 

Uses. — The  material,  aside  from  its  use  as  a  gem,  owes  its  chief 
value  to  its  great  hardness,  and  is  used  as  an  abrading  and  cutting 
medium  in  cutting  diamonds  and  other  gems,  glass,  and  hard  materials 
in  general,  such  as  can  not  be  worked  by  softer  and  cheaper  sub- 
stances. 

With  the  introduction  of  machinery  into  mining  and  quarrying 
there  has  arisen  a  constant  and  growing  demand  for  black  diamonds, 
or  bort,  for  the  cutting  edges  of  diamond  drills,  and  to  a  less  extent 
for  teeth  to  diamond  saws. 

The  crystallized  diamond  is  not  suitable  for  these  purposes 
owing  to  its  cleavage  property.  The  best  bort  or  carbonado 
comes,  it  is  said,  from  Bahia,  Brazil,  where  it  is  found  as  small, 
black  pebbles  in  river  gravels.  The  ordinary  sizes  used  for  drills 
weigh  but  from  one-half  to  i  carat,  but  in  special  cases  pieces  weigh- 
ing from  4  to  6  carats  are  used.  It  is  stated  that  the  crowns  of  large 
drills,  10  inches  in  diameter,  armed  with  the  best  grade  of  carbonado, 
are  sometimes  valued  as  high  as  $10,000. 

BIBLIOGRAPHY. 

M.  BABINET.     The  Diamond  and  other  precious  stones. 

Report  of  the  Smithsonian  Institution,  1870,  p.  333. 
A.  DAUBREE.     Annales  des  Mines,  7th  Ser.,  IX,  1876,  p.  130. 

Remarking  on  the  occurrence  of  platinum  associated  with  peridotites,  he  calls 
attention  to  the  fact  that  Maskelyne  had  shown  the  diamonds  of  South  Africa 
and  Borneo  to  occur  in  a  decomposed  peridotite. 

ORVILLE  A.  DERBY.     Geology  of  the  Diamantiferous  Region  of  the  Province  of 
Parana,  Brazil. 

American  Journal  of  Science,  XVIII,  1879,  p.  310. 
Geology  of  the  Diamond. 

American  Journal  of  Science,  XXIII,  1882,  p.  97. 
R.  COHEN.     Igneous  origin  of  the  Diamond. 

Proceedings,  Manchester  Literary  and  Philosophical  Society,  1884,  p.  5. 


6  THE  NON-METALLIC  MINERALS. 

H.  CARVILL  LEWIS.     The  Genesis  of  the  Diamond. 

Science,  VIII,  1886,  p.  345. 
GARDNER  F.  WILLIAMS.     The  Diamond  Mines  of  South  Africa. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XV,  1886,  p.  392. 
ORVILLE  A.  DERBY.     The  Genesis  of  the  Diamond. 

Science,  IX,  1887,  p.  57. 
Discovery  of  Diamonds  in  a  Meteoric  Stone. 

Nature,  XXXVII,  1887,  p.  no. 
Diamond  Mining  in  Ceylon. 

Engineering  and  Mining  Journal,  XLIX,  1890,  p.  678- 
A.  MERVYN  SMITH.     The  Diamond  Fields  of  India. 

Engineering  and  Mining  Journal,  LIII,  1892,  p.  454. 
OLIVER  WHIPPLE  HUNTINGTON.     Diamonds  in  Meteorites. 

Science,  XX,  1892,  p.  15. 
Diamonds  in  Meteoric  Stones. 

The  American  Geologist,  XI,  1893,  p.  282.     (Abstract  of  paper  by  H.  Moissan, 
Comptes  Rendus  1893,  pp.  116  and  228.) 
HENRI  MOISSAN.     Study  of  the  Diamantiferous  Sands  of  Brazil. 

Engineering  and  Mining  Journal,  LXII,  1896,  p.  222. 

HENRY  CARVILL  LEWIS.     I.  Papers  and  Notes  on  the  Genesis  and  Matrix  of  the 
Diamond,  edited  by  Prof.  T.  G.  Bonney. 

The  Geological  Magazine,  IV,  1897,  p.  366. 
Sir  WILLIAM  CROOKES.     Diamonds. 

Nature,  LV,  1897,  p.  325. 
L.  DE  LAUNAY.     Les  Diamants  du  Cap. 

Paris,    1897. 
ORVILLE  A.  DERBY.     Brazilian  Evidence  on  the  Genesis  of  the  Diamond. 

The  Journal  of  Geology,  VI,  1898,  p.  121. 
H.  W.  FURMISS.     Carbons  in  Brazil.     U.  S.  Consular  Reports,  1898,  p.  604.     See  also 

Engineering  and  Mining  Journal,  LXVI,  1898,  p.  608. 
M.  J.  KLINCKE.     Gttes  Diamantiferes  de  la  Republique  sud-Africaine. 

Annales  des  Mines,  XIV,  1898,  p.  563. 
GARDNER  F.  WILLIAMS.     The  Diamond  Mines  of  South  Africa.     The  Macmillan 

Company,  London,  1902. 
GEORGE  F.  KUNZ  and  H.  S.  WASHINGTON.     Diamonds  in  Arkansas. 

Transactions  American  Institute  of  Mining  Engineers,  XXXIX,  1908,  p.  169. 
J.  C.  BRANNER.     The  Diamond-Bearing  Highlands  of  Brazil. 

Engineering  and  Mining  Journal,  LXXXVII,  1909,  p.  981. 

VICTOR  HARTOG.     Petrographic  Notes  on  the  Diamond-bearing  Peridotites  of  Kim- 
berly,  South  Africa. 

Economic  Geologist,  IV,  No.  5,  1909,  p.  438.     This   paper  gives  full   bibliog- 
raphy of  African  mines  up  to  date. 

Graphite. — Graphite,  plumbago,  or  black  lead,  as  it  is  variously 
called,  is  a  dark  steel-gray  to  black  lustrous  mineral  with  a  black 
streak,  a  hardness  of  but  1.2,  and  a  specific  gravity  of  from  2.25  to 
2.27.  The  prevailing  form  of  the  mineral  is  scaly  or  broadly  foliated, 


ELEMENTS.  7 

with  a  bright  luster,  but  it  is  sometimes  quite  massive  and  columnar 
or  earthy,  with  a  dull  coal-like  luster. 

Its  most  characteristic  features  are  its  softness,  greasy  feeling, 
and  property  of  soiling  everything  with  which  it  comes  in  contact. 
Molybdenite,  the  sulphide  of  molybdenum,  is  the  only  mineral  with 
which  it  is  likely  to  become  confounded.  This  last,  however,  though 
very  similar  in  general  appearance,  gives  a  streak  with  a  slight 
greenish  tinge,  and  when  fused  with  soda  before  the  blowpipe  yields 
a  sulphur  reaction.  Chemically,  graphite  is  nearly  pure  carbon. 
The  name  black  lead  is  therefore  erroneous  and  misleading,  but  has 
become  too  firmly  established  to  be  easily  eradicated. 

The  analyses  given  below  show  the  composition  of  some  of  the 
purest  natural  graphites. 


Locality. 

Carbon. 

Ash. 

Volatile 
Matter. 

Ceylon 

08  817 

o  280 

O   OO 

Do 

00    702 

o£ 

«8 

Buckingham   Canada 

Q7    626 

i   78 

<\Qd 

Do 

GO   8l  C 

076 

TQQ 

As  mined  the  material  is  almost  invariably  contaminated  by 
mechanically  admixed  impurities.  Thus  the  Canadian  material  as 
mined  yields  from  22.38  to  30.51  per  cent  of  graphite;  the  best 
Bavarian,  53.80  per  cent.  The  grade  of  ore  that  can  be  economi- 
cally worked  naturally  depends  upon  the  character  of  the  impurities 
and  the  extent  and  accessibility  of  the  deposit.  It  is  said1  that 
deposits  at  Ticonderoga,  New  York,  have  been  worked  in  which 
there  was  but  6  per  cent  of  graphite. 

Occurrence  and  origin. — Graphite  occurs  mainly  in  the  older 
crystalline  metamorphic  rocks,  both  siliceous  and  calcareous,  some- 
times in  the  form  of  disseminated  scales,  as  in  the  crystalline  lime- 
stone of  Essex  County,  New  York,  or  in  embedded  masses,  streaks, 
and  lumps,  often  of  such  dimensions  that  .single  blocks  of  several 
hundred  pounds  weight  are  obtainable.  It  is  also  found  in  the 
form  of  true  beds  and  veins. 

The  fact  that  the  mineral  is  carbon,  one  of  the  constituents  of 


1  Engineering  and  Mining  Journal,  LXV,  1898,  p.  256. 


8  THE  NON-METALLIC  MINERALS. 

animal  and  vegetable  life,  has  led  many  authorities  to  regard  it,  like 
coal,  as  of  vegetable  orgin.  While  this  view  is  very  plausible  it 
can  not,  however,  be  regarded  as  in  all  cases  proven. 

That  graphite  may  be  formed  independently  of  organic  life  is 
shown  by  its  presence  in  cast  iron,  where,  on  cooling,  it  has  crys- 
tallized out,  in  the  form  of  bright  metallic  scales. 

Carbon  is  also  found  in  meteorites  which  are  plainly  of  igneous 
origin,  and  which  have  thus  far  yielded  no  certain  traces  of  either 
plant  or  animal  remains.  It  is,  however,  a  well-known  fact  that 
coal — itself  of  organic  origin — has  in  some  cases  been  converted  into 
graphite  through  metamorphic  agencies,  and  intermediate  stages  like 
the  graphitic  anthracite  of  Newport,  Rhode  Island,  afford  good 
illustrations  of  such  transitions.  Certain  European  authorities1  have 
shown  that  amorphous  carbonaceous  particles  in  clay  slates  have 
been  converted  into  graphite  by  the  metamorphosing  influence  of 
intruded  igneous  rocks.  Prof.  J.  S.  Newberry  described  an  occur- 
rence of  this  nature  in  the  coal  fields  of  Sonora,  Mexico,2  as  follows: 

"  All  the  western  portion  of  this  coal  field  seems  to  be  much  broken 
by  trap  dikes  which  have  everywhere  metamorphosed  the  coal  and 
converted  it  into  anthracite.  At  the  locality  examined  the  metamorphic 
action  has  been  extreme,  converting  most  of  the  coal  into  a  brilliant 
but  somewhat  friable  anthracite,  containing  3  or  4  per  cent  of  volatile 
matter.  At  an  outcrop  of  one  of  the  beds,  however,  the  coal  was 
found  converted  into  graphite,  which  has  a  laminated  structure, 
but  is  unctuous  to  the  touch  and  marks  paper  like  a  lead  pencil. 
The  metamorphism  is  much  more  complete  than  at  Newport  (Rhode 
Island),  furnishing  the  best  example  yet  known  to  me  of  the  con- 
version of  a  bed  of  coal  into  graphite." 

In  New  York  State  and  in  Canada,  graphite  occurs  in  Laurentian 
rocks,  both  in  beds  and  in  veins,  a  portion  of  the  latter  being  appar- 
ently true  fissure  veins  and  others  shrinkage  cracks  or  segregation 
veins  which  traverse  in  countless  numbers  the  containing  rocks.  It  is 
said3  that  in  the  Canadian  regions  the  deposits  occur  generally  in 

1  Beck  and  Luzi,  Berichte  der  Deutschen  Chemischen  Gesellschaft,  1891,  p.  24. 

2  School  of  Mines  Quarterly,  VIII,  1887,  p.  334. 

3  See  On  the  Graphite  of  the  Laurentian  of  Canada,  by  J.  W.  Dawson,  Proceedings 
of  the  Geological  Society  of  London,  XXV,  1870,  p.  112,  and  an  article  on  Graphite 
by  Prof.  J.  F.  Kemp  in  The  Mineral  Industry,  II,  1893,  p.  335. 


ELEMENTS.  9 

limestone  or  in  their  immediate  vicinity,  and  that  granular  varieties 
of  the  rock  often  contain  large  crystalline  plates  of  the  mineral. 
At.  other  times  the  mineral  is  so  finely  disseminated  as  to  give  a 
bluish-gray  color  to  the  limestone,  and  the  distribution  of  the  bands 
thus  colored  seems  to  mark  the  stratification  of  the  rock.  Further, 
the  plumbago  is  not  confined  to  the  limestones;  large  crystalline 
scales  of  it  are  occasionally  disseminated  in  pyroxene  rock  or  pyraL 
lolite,  and  sometimes  in  quartzite  and  in  feldspathic  rocks,  or  even 
in  magnetic  oxide  of  iron.  In  addition  to  these  bedded  forms, 
there  are  also  true  veins  in  which  graphite  occurs  associated  with 
calcite,  quartz,  orthoclase,  or  pyroxene,  and  either  in  disseminated 
scales,  in  detached  masses,  or  in  bands  or  layers  separated  from 
each  other  and  from  the  wall  rock  by  feldspar,  pyroxene,  and  quartz. 
Kemp  describes1  the  graphite  deposit  near  Ticonderoga,  New  York, 
as  in  the  form  of  a  true  fissure  vein,  cutting  garnetiferous  gneiss, 
which  has  an  east  and  west  strike.  The  vein  at  the  "big  mine" 
runs  north  12°  west,  and  dips  55°  west.  The  vein  filling  is  evidently 
orthoclase  (or  microcline)  with  quartz  and  biotite  and  pockets  of 
calcite.  Besides  graphite,  it  contains  tourmaline,  apatite,  pyrite, 
and  sphene. 

Walcott2  describes  the  graphite  at  the  mines  4  miles  west  of 
Hague,  on  Lake  George,  New  York,  as  occurring  in  Algonkian 
rocks,  and  as  probably  of  organic  origin. 

At  the  mines  the  alternating  layers  of  graphite  shale  or  schist 
form  a  bed  varying  from  3  to  13  feet  in  thickness.  The  outcrop  may 
be  traced  for  a  mile  or  more.  The  garnetiferous  sandstones  form  a 
strong  ledge  above  and  below  the  graphite  bed.  The  appearance 
is  that  of  a  fossil  coal  bed,  the  alteration  having  changed  the  coal 
to  graphite  and  the  sandstone  to  indurated,  garnetiferous,  almost 
quartzitic  forms.  The  character  of  the  graphite  bed  is  well  shown 
in  the  accompanying  plate  (PL  I),  from  a  photograph  taken  in  1890. 
It  is  here  a  little  over  9  feet  in  thickness  and  is  formed  of  alternating 
layers  of  highly  graphitic  sandy  shale  and  schist. 


1  Preliminary  Report  on  the  Geology  of  Essex  County,  Contributions  from  the  Geo- 
logical Department  of  Columbia  College,  1893,  pp.  452,  453. 

2  Bulletin  of  the  Geological  Society  of  America,  X,  1898,  p.  227. 


10  THE  NON-VIETALLIC   MINERALS. 

F.  L.  Hess  describes1  the  graphite  of  Santa  Maria,  Mexico,  as 
occurring  in  beds  in  sandstone  which  has  been  much  folded  and  also 
intruded  by  granitic  dikes.  There  are  at  least  seven  beds  of  varying 
thickness.  The  folding  to  which  the  enclosing  sandstone  has  been 
subjected  has  in  many  instances  so  squeezed  the  yielding  graphite 
as  to  form  lenticular  masses,  in  places  upward  of  20  feet  in  thickness 
which  within  a  short  distance  may  pinch  out  to  mere  knife-like  edges. 
The  wall  rock  of  the  mines,  as  may  be  surmised  from  the  above,  is 
mainly  sandstone,  though  sometimes  of  granite.  The  graphite  is 
wholly  amorphous,  but  is  said  to  be  very  pure.  It  would  appear 
to  owe  its  origin  to  the  metamorphism  of  beds  of  coal  through  the 
intrusion  of  igneous  rocks,  as  in  the  case  described  by  Newberry. 

According  to  J.  Walther2  the  Ceylonese  graphite  occurs  in 
coarsely  foliated  or  stalky  masses  in  veins  in  gneiss  which,  where 
mined,  is  decomposed  to  the  condition  of  laterite.  The  veins  are 
regarded  as  true  fissures,  and  vary  from  12  to  22  cm.  (about  4!  to 
8J  inches)  in  width. 

The  graphite  of  Northern  Moravia  occurs  in  gray  to  black 
crystalline  granular  Archaean  limestone  interbedded  with  amphibo- 
lites  and  muscovite  gneiss,  the  limestone  itself  being  often  serpen- 
tinous,  in  this  respect  apparently  resembling  the  graphitic  portions 
of  the  ophicalcites  of  Essex  County,  New  York.  The  material  is 
quite  impure,  showing  on  the  average  but  53  per  cent  of  carbon 
and  44  per  cent  of  ash,  the  latter  being  made  up  largely  of  silica 
and  iron  oxide,  with  a  little  sulphur,  magnesia,  and  alumina.  This 
graphite  is  regarded  as  originating  through  the  metamorphism  of 
vegetable  matter  included  in  the  original  sediments,  the  agencies 
of  metamorphism  being  both  igneous  intrusions  and  the  heat  and 
pressure  incidental  to  the  folding  of  the  beds.3 

As  to  so  much  of  the  graphite  as  occurs  in  beds  there  seems, 
then,  little  doubt  as  to  its  origin  from  plant  remains  which  may  be 
imagined  to  have  existed  in  the  form  of  seaweeds  or  to  have  been  de- 
rived from  diffused  bituminous  matter.  The  origin  of  the  vein 
material  is  not  so  evident,  though  it  seems  probable  that  it  is  due 

1  Engineering  Magazine,  XXXVIII,  1909,  pp.  36-48. 

3  Records  of  the  Geological  Survey  of  India,  XXIV,  1891,  p.  42. 

»  Jahrbuch  k.  k.  Geologische  Reichsanstalt,  1897,  XLVII,  p.  21. 


ELEMENTS.  1 1 

to  the  rnetamorphism  of  bituminous  matter  segregated  into  veins, 
like  those  of  albertite  in  New  Brunswick  or  of  gilsonite,  in  Utah. 
Kemp  states  that  the  Ticonderoga  graphite  must  have  reached  the 
fissure  as  some  volatile  or  liquid  hydrocarbon,  such  as  petroleum, 
and  become  metamorphosed,  in  time,  to  its  present  state.  Walther 
believes  the  Ceylon  material  to  have  originated  by  the  reduction 
of  carburetted  vapors.  (See  also  under  origin  of  diamonds, 

p.     2.) 

The  total  quantity  of  carbon  in  the  form  of  graphite  in  the  Lauren- 
tian  rocks  of  Canada  has  been  estimated  by  Dawson  as  equal  to  that 
in  the  form  of  coal  in  any  similar  areas  of  the  Carboniferous  system  of 
Pennsylvania. 

Sources. — The  chief  sources  of  the  graphite  of  commerce  are 
Austria  and  Ceylon.  Other  sources  of  commercial  importance  are 
Germany,  Italy,  Siberia,  the  United  States,  Canada  and  Mexico. 
The  chief  deposits  of  commercial  value  in  the  United  States  are  at 
Ticonderoga,  and  Hague,  N.  Y.,  and  Clay  County,  Alabama,  where 
the  material  occurs  in  disseminated  scales  in  a  mica-free  granite. 
An  earthy,  impure  graphite,  said  to  be  suitable  for  foundry  facings, 
is  mined  near  Newport,  Rhode  Island.  In  Chester  County,  Penn- 
sylvania, the  material  is  mined  from  deposits  in  mica  schist.  Other 
American  localities  are:  Bartow  County,  Georgia;  Bloomingdale, 
New  Jersey;  Clintonville,  New  York;  Wake  County,  North  Caro- 
lina; Lehigh  and  Berks  counties,  Pennsylvania;  Salt  Sulphur  Springs, 
West  Virginia;  St.  Johns,  Tooele  County,  Utah. 

Near  Centersville,  Georgia,  there  is  mined  from  open  cuts  a 
graphitic  schist  consisting  essentially  of  from  5  to  10  per  cent  of 
amorphous  graphite  and  talcose  minerals,  which  presumably  origi- 
nated through  the  rnetamorphism  of  carbonaceous  slates. 

Graphite  is  a  very  common  mineral  in  the  Laurentian  rocks  of 
Canada.  The  most  important  known  localities  are  north  of  the 
Ottawa  River,  in  the  townships  of  Buckingham,  Lochaber,  and 
Grenville.  At  Buckingham  it  is  stated  masses  of  graphite  have 
been  obtained  weighing  nearly  5,000  pounds.  At  Grenville  the 
graphite  occurs  in  a  gangue  consisting  mainly  of  pyroxene,  wollas- 
tonite,  feldspar,  and  quartz,  while  the  country  rock  is  limestone. 


12  THE  NON-METALLIC  MINERALS. 

Blocks  of  graphite  have  been  obtained  weighing  from  700  to  i,soo 
pounds.1 

Graphite  is  also  found  in  Japan,  Australia,  New  Zealand,  Green- 
land, Guatemala,  Germany,  and  in  almost  all  the  Austrian  provinces; 
the  most  important  and  best  known  deposits  being  those  of  Kaiser- 
berg  at  St.  Michel,  where  there  are  five  parallel  beds  occurring  in 
a  grayish-black  graphite  schist,  the  beds  varying  from  a  few  inches 
to  6  yards.  The  only  workable  deposit  in  Germany  is  stated  to  be 
at  Passau  in  Bavaria.  The  material  occurs  in  a  feldspathic  gneiss, 
seeming  to  take  the  place  of  the  mica.  The  beds  have  been  worked 
chiefly  by  peasants  for  centuries,  and  the  output  used  mainly  for 
crucibles.2 

Uses. — Graphite  is  used  in  the  manufacture  of  "lead"  pencils, 
lubricants,  stove  blacking,  paints,  refractory  crucibles,  and  for 
foundry  facings.  In  the  manufacture  of  pencils  only  the  purest 
and  best  varieties  are  used,  and  high  grades  only  can  be  utilized  for 
lubricants.  For  the  other  purposes  mentioned  impure  materials  can 
be  made  to  answer.  In  the  manufacture  of  the  Dixon  crucibles, 
a  mixture  of  50  per  cent  graphite,  33  per  cent  of  clay,  and  17  per 
cent  of  sand  is  used. 

The  low  grade  graphitic  material  obtained  from  graphitic  schists, 
near  Centersville,  Georgia,  is  used  as  a  "filler"  in  the  manufacture 
of  fertilizers,  it  being  claimed  for  it  that  it  prevents  absorption  of 
moisture,  and  incidental  caking. 

Preparation. — In  nature  graphite  is  usually  associated  with  harder 
and  heavier  materials,  which  it  is  necessary  to  eliminate  before 
the  material  is  of  value.  In  New  York  it  is  the  custom  to  crush 
the  rock  in  a  battery  of  stamps,  such  as  are  used  in  gold  milling, 
and  then  separate  the  graphite  by  washing,  its  lighter  specific  gravity 
permitting  it  to  be  floated  off  on  water,  while  the  heavy,  injurious 
constituents  are  left  behind.  Mica,  owing  to  its  scaly  form,  can  not 
be  separated  in  this  manner,  and  hence  micaceous  ores  of  the  mineral 
are  of  little  if  any  value. 

1  Descriptive  Catalogue  of  Economic  Minerals  of  Canada,  1876,  p.  122. 

2  The  Journal  of  the  Iron  and  Steel  Institute,  1890,  p.  739. 


ELEMENTS  13 

Prices. — The  value  of  the  mineral  varies  with  its  quality.  In 
1907  the  crude  lump  was  reported  as  worth  $8  a  ton  and  the  pulver- 
ized $30. 

The  annual  output  as  given  1  for  the  principal  countries  is  as  fol- 
lows: 


WORLD'S  PRODUCTION  OF  GRAPHITE. 


Year. 

Austria. 

Canada. 

Mexico. 

Germany. 

India, 

Italy. 

United 
States. 

IQOO   ' 

Metric 
tons. 
T.T.  663 

Metric 
tons. 
I  74T 

Metric 
tons. 
2  c6l 

Metric 
tons. 
0  24.8 

Metric 
tons. 
I  858 

Metric 
tons. 
9  7  2O 

Metric 
tons. 
I  862 

IQO7.  . 

40,425 

C2C 

3,202 

4.OT.T. 

2,472 

0,260 

2,080 

Ceylon  produced 
produced  artificially 
New  York. 


in  1906,  36,578  tons.     Some  7,000,000  pounds  of  graphite  are 
by   the   International   Graphite   Company,   at    Niagara    Falls, 


BIBLIOGRAPHY. 

J.  W.  DAWSON.     On  the  Graphite  of  the  Laurentian  of  Canada. 

Quarterly  Journal  Geological  Society  of  London,  XXVI,  1870,  p.  112. 
M.  BONNEFOY.     Memoire  sur  la  Geologie  et  PExploitation  des  Gites  de  Graphite  de 
la  Boheme  Meridionale. 

Annales  des  Mines,  7th  Ser.,  XV,  1879,  p.  157. 
JOHN  S.  NEWBERRY.     The  Origin  of  Graphite. 

School  of  Mines  Quarterly,  VIII,  1887,  p.  334. 
Der  Graphitbergbau  auf  Ceylon. 

Berg-  und  Huttenmannische  Zeitung,  XLVII,  1888,  p.  322. 
J.  WALTHER.     Ueber  Graphitgange  in  zersetztem  Gneiss  (Laterit)  von  Ceylon. 

Zeitschrift  der  Deutschen  Geologischen  Gesellschaft,  XLI,  1889,  p.  359. 
A.  PALLAUSCH.     Die  Graphitbergbaue  im  siidlichen  Bohmen. 

Berg-  und  Huttenmarnisches  Jahrbuch,  XXXVII,  1889,  p.  95. 
T.  ANDREE.     Graphite  Mining  in  Austria  and  Bavaria.     (Abstract.) 

Journal  of  the  Iron  and  Steel  Institute,  1890,  p.  738. 

J.  POSTLETHWAITE.     The    Borrowdale    Plumbago;     its   Mode    of   Occurrence   and 
Probable  Origin. 

Proceedings  of  the  Geological  Society  of  London,  Session,  1889-90,  p.  124. 
On  the  formation  of  Graphite  in  contact-metamorphism. 

American  Journal  of  Science,  XLII,  1891,  p.  514.      Review  of  article  in  Be- 
richte  der  Deutschen  Chemischen  Gesellschaft,  XXIV,  p.  1884,  1891. 


1  The  Mineral  Industry,  VI,  1897;  VIII,  1899. 


14  THE  NON-METALLIC  MINERALS. 

W.    Luzr.     Zur    Kenntniss    des    Graphitkohlenstoffes.     (Berichte    der    Deutschen 
Chemischen  Gesellschaft,  XXIV,  pp.  4085-4095.     1891.) 

Neues  Jahrbuch  fiir  Mineralogie,  Geologic  und  Paleontologie.     1893.     II,  Part 
2,  p.  241.     (Abstract.) 

E.   WEINSCHENK.     Zur   Kenntniss   der   Graphitlagerstatten.     Chemisch-geologische 
Studien  von  Dr.  Ernst  Weinschenk. 

i.  Die    Graphitlagerstatten    des    bayerischen    Grenzgebirges.     Habilitations- 
schrift  zur  Erlangung  der  venia  legendi  an  der  K.   technischen  Hochschule. 
Miinchen,  1897. 
FRANZ  KRETSCHMER.     The  Graphite  Deposits  of  Northern  Moravia. 

Transactions  of  the  North  of  England  Institute  of  Mining  and  Mechanical 
Engineering,  XL VII,  1898,  p.  87. 

2.   SULPHUR. 

The  color  of  this  mineral  when  pure  is  yellow,  sometimes  brownish, 
reddish,  or  gray  through  impurities.  Hardness,  1.5  to  2.5.  Specific 
gravity,  2.05.  Insoluble  in  water  or  acids.  Luster  resinous.  It 
occurs  native  in  beautiful  crystals,  or  in  massive,  stalactitic  and  sphe- 
roidal forms.  Once  seen  the  mineral  is  as  a  rule  readily  recognized, 
and  all  possible  doubts  are  set  at  rest  by  its  ready  burning  with  a 
faint  bluish  flame  and  giving  the  irritating  odors  of  sulphurous  anhy- 
dride. In  nature  it  is  often  impure  through  the  presence  of  clay  and 
bituminous  matters,  and  sometimes  contains  traces  of  selenium  or 
tellurium. 

Origin  and  mode  of  occurrence. — Sulphur  deposits  of  such  extent 
as  to  be  of  economic  importance  occur  as  a  product  of  volcanic 
activity,  or  result  from  the  alteration  of  beds  of  gypsum.  On  a 
smaller  scale,  and  of  interest  from  a  purely  mineralogical  standpoint, 
are  the  occurrences  of  sulphur  through  the  alteration  of  pyrite  and 
other  metallic  sulphides. 

As  a  product  of  volcanic  action  sulphur  is  formed  through  the 
oxidation  of  hydrogen  sulphide  (H2S),  which,  together  with  steam 
and  other  vapors,  is  a  common  exhalation  from  volcanic  vents  and 
solfataras.  Such  deposits  on  a  small  scale  may  be  seen  incrusting 
fumaroles  in  the  Roaring  Mountain  or  associated  with  the  sinter 
deposits  of  the  Mammoth  Hot  Springs  in  the  Yellowstone  Park.  It 
may  also  be  produced  through  the  mutual  reaction  of  hydrogen 
sulphide  (H2S)  on  sulphuric  anhydride  (SO2),  the  product  being 
sulphur  (S)  and  water  (H2O)  as  before.  To  these  types  belong  the 


ELEMENTS.  15 

sulphur  deposits  of  Utah,  California,  Nevada,  and  Alaska  in  the 
United  States,  as  well  as  those  of  Mexico,  Japan,  Iceland,  and  other 
volcanic  regions.  Sulphur  is  derived  from  the  sulphate  of  lime  (gyp- 
sum or  anhydrite)  through  the  reducing  action  of  organic  matter. 
The  sulphate,  through  the  loss  of  its  oxygen,  becomes  converted  into  a 
sulphide,  which,  through  the  carbonic  acid  in  the  air  and  water, 
becomes  finally  reduced  to  hydrogen  sulphide  with  the  formation  of 
calcium  carbonate. 

According  to  Fuchs  and  De  Launay1  there  is  formed  at  the  same 
time  with  the  hydrogen  sulphide,  a  polysulphide,  which  in  its  turn 
yields  a  precipitate  of  sulphur  and  carbonate  of  lime.  The  maxi- 
mum amount  of  sulphur  which  would  thus  result  from  the  decompo- 
sition of  a  given  amount  of  gypsum  is  stated  to  be  24  per  cent.  This 
method  of  origin  is  illustrated  in  the  celebrated  deposit  of  Sicily, 
where  the  sulphur  occurs  partially  disseminated  through  and  partly 
interbedded  with  a  blue-gray  limestone.  Beneath  the  sulphur  beds 
as  they  now  exist  are  found  the  remnants  of  the  older  gypseous  beds, 
which  through  decomposition  have  yielded  the  materials  for  the  lime 
and  sulphur  beds  now  overlying. 

With  these  Sicilian  sulphurs  occur  a  number  of  beautiful  secondary 
minerals,  as  celestite,  calcite,  aragonite,  and  selenite. 

Sulphur  derived  directly  from  metallic  sulphides  is  of  little 
economic  interest.  Kemp  states2  that  masses  of  pyrite  in  the  cal- 
ciferous  strata  on  Lake  Champlain  may  yield  crusts  of  sulphur  an 
inch  or  so  thick,  and  it  is  not  uncommon  to  find  small  crystals  of 
the  mineral  resulting  from  the  alteration  of  galena,  as  described  by 
George  H.  Williams,3  at  the  Mountain  View  (Maryland)  lead  mine. 

The  minute  quantities  of  sulphur  found  in  marine  muds  are 
regarded  by  J.  Y.  Buchanan4  as  due  to  the  oxidation  of  metallic 
sulphides,  which  are  themselves  produced  by  the  action  of  animal 
digestive  secretions  on  preexisting  sulphates,  mainly  of  iron  and 
manganese. 

Localities.  —  The  principal  localities  of  sulphur  known  in  the 
United  States  are,  in  alphabetical  order:  Alaska,  California,  Idaho, 

1  Traite  des  Gites  Mineraux  et  Metalliferes,  I,  p.  259. 

2  The  Mineral  Industry,  II,  1893,  p.  585. 

3  Johns  Hopkins  University  Circulars,  X,  1891,  p.  74. 

4  Proceedings  of  the  Royal  Society  of  Edinburgh,  XVIII,  1890-91,  p.  17. 


i6 


THE   NON-METALLIC  MINERALS. 


Louisiana,  Nevada,  Texas,  Utah,  and  Wyoming.  With  the  possible 
exception  of  those  of  Louisiana,  these  may  all  be  traced  to  a  solfataric 
origin.  The  Alaskan  deposits,1  according  to  Dall,  are  best  developed 
on  the  islands  of  Kadiak  and  Akutan.  California  deposits  have  in 
times  past  been  worked  at  Clear  Lake,  in  Modoc  County,  in  Colusa 
County,  in  Tehama  County,  and  in  Napa  County.  The  Louisiana 
deposits  lie  in  strata  of  Quaternary  Age,  and  are  derived  from 
gypsum.  The  following  facts  relative  to  this  deposit  are  from  Pro- 
fessor Kemp's  paper,  already  alluded  to: 

Probably  the  richest  and  geographically  the  most  accessible  of 
the  American  localities  is  in  the  southwestern  part  of  the  State,  230 
miles  west  of  New  Orleans  and  12  miles  from  Lake  Charles.  The 
first  hole  which  revealed  sulphur  was  sunk  in  search  of  petroleum. 
While  more  or  less  bituminous  matter  was  revealed  by  the  drill,  the 
great  bed  of  sulphur  is  the  main  object  of  interest.  A  number  of  holes 
have  since  been  put  down  with  the  results  recorded  below,  leaving 
no  doubt  but  that  there  is  a  very  large  body  which  awaits  exploitation. 
The  first  explorations  were  made  by  the  Louisiana  Petroleum  and 
Coal  Oil  Company.  This  was  succeeded  by  the  Calcasieu  Sulphur 
and  Mining  Company.  The  Louisiana  Sulphur  Mining  Company 
followed,  and  finally  the  American  Sulphur  Company.  The  records 
of  8  holes  are  appended.  Nos.  i  and  2  are  about  150  feet  apart. 
Nos.  2,  3,  and  4  were  put  down  in  1886. 

RECORDS  OF  BORE-HOLES  THAT  HAVE   PENETRATED  THE   SULPHUR  BED. 


Strata. 

Original 
Well 
No.  i. 

Granet's  Wells. 

Van 
Sloot- 
en's 
Well 
No.  5. 

American  Sulphur 
Company. 

No.  2. 

No.  3. 

No.  4. 

No.  6. 

No.  7. 

No.  8. 

Clay,  quicksand,  and  gravel.  .  . 
Soft  rock  .  . 

333 
no 
108 
680 

344 
84 

112 
12 

426 
70 
IIQ 
6 

332 
138 

45 
(") 

345 
91 
no 

57 

35° 
95 
125 
32 

37° 
72 
126 

3° 

499 
44 

(aT 

Sulphur  bed,  70  to  80  per  cent. 
Gypsum  and  sulphur.  .  ....... 

Depth  of  hole  in  feet  

1,231 

552 

621 

525 

603 

602 

598 

596 

a.  Stopped  in  sulphur. 


Alaska  and  its  Resources,  Boston,  1870. 


ELEMENTS. 


Analyses  from  the  large  bed  in  holes  No.  2  and  No.  3  gave  the 
following : 


Depth. 

Sulphur. 

Depth. 

Sulphur. 

Hole  No,  2. 
428  feet 

Percent. 
62 

Hole  No.  3. 
!    ZOT,  feet.  . 

Per  cent. 
7O 

7O 

c  7  -2  feet.  . 

60 

80 

s4Q  feet.  . 

81 

466  feet 

83 

r  r  2  feet 

OI 

486  feet 

GO 

604  feet.  .             

08 

—  feet   

80 

feet   

feet     

80 

CAQ  feet 

68 

The  difficulties  in  development  which  have,  however,  been  largely 
overcome,  lie  in  the  quicksands  and  gravel,  which  are  wet  and  soft, 
and  in  the  soft  rock  (hole  i),  which  yields  sulphurous  waters  under  a 
head,  at  the  surface,  of  about  15  feet. 

Sulphur  deposits,  supposedly  due  to  the  oxidation  of  sulphuretted 
hydrogen,  occur  over  wide  areas  in  northern  El  Paso  and  Reeves 
counties  in  Texas.  The  country  rock  is  limestone  and  the  sulphur 
wholly  superficial  and  associated  with  gypsum  or  loosely  consolidated 
detritus  of  the  nature  of  sand  and  gravel. 

Nevada. — The  Nevada  deposits  occupy  the  craters  of  extinct 
hot  springs  near  Humboldt  House.  These  craters  or  cones  are 
described  by  Russell l  as  situated  on  the  open  desert,  above  the  surface 
of  which  they  rise  to  a  height  of  from  20  to  50  feet. 

Nearly  all  of  the  cones  are  weathered  and  broken  down,  and 
are  all  extinct.  The  outer  surface  of  the  cones  is  composed  of  cal- 
careous tufa  and  siliceous  sinter,  forming  irregular  imbricated  sheets 
that  slope  away  at  a  low  angle  from  the  orifice  at  the  top.  The 
interiors  of  these  structures  are  filled  with  crystalline  gypsum,  which 
in  at  least  two  instances  is  impregnated  with  sulphur.  One  of  the 
cones  has  been  opened  by  a  cut  from  the  side  in  such  a  manner  as 
to  expose  a  good  section  of  the  material  filling  the  interior,  and  a  few 
tons  of  the  sulphur  and  gypsum  removed.  The  percentage  of  sul- 
phur is  small,  and  the  economic  importance  of  the  deposit  somewhat 
doubtful.  The  cone  that  has  been  opened  is  surrounded  on  all  sides 

1  Transactions  of  the  New  York  Academy  of  Sciences,  I,  1881-1882,  p.  172. 


1 8  THE  NON-METALLIC  MINERALS. 

by  a  large  deposit  of  calcareous  and  siliceous  material,  thus  forming 
a  low  dome  or  crater,  with  a  base  many  times  as  great  in  diameter 
as  the  height  of  the  deposit.  These  cones  correspond  in  all  their 
essential  features  with  the  structures  that  surround  hot  springs  that 
are  still  active  in  various  parts  of  the  Great  Basin,  thus  leaving  no 
question  as  to  their  origin.  They  are  situated  within  the  basin  of 
Lake  Lahontan,  and  must  have  been  formed  and  become  extinct 
since  the  old  lake  evaporated  away. 

Sulphur  is  reported  as  occurring  in  the  chemically  formed  deposits 
that  surround  Steamboat  Springs,  situated  midway  between  Car- 
son and  Reno,  Nevada,  and  in  the  Sweetwater  Mountains,  on  the 
boundary  between  California  and  Nevada.  The  extent  and  geolog- 
ical relations  of  these  last  mentioned  deposits  are  unknown. 

Another  illustration  of  deposits  of  the  volcanic  type  is  that  fur- 
nished by  the  Rabbit-Hole  Sulphur  Mines.  These  are  located  in 
northwestern  Nevada,  on  the  eastern  border  of  the  Black  Rock 
Desert,  and  derive  their  name  from  the  Rabbit-Hole  Springs,  a 
few  miles  to  the  southward.  The  hills  bordering  on  the  east  are 
mainly  of  rhyolite,  with  a  narrow  band  of  water-laid  volcanic  tuff 
along  the  immediate  edge  of  the  desert.  At  the  mines  the  angular 
fragments  of  volcanic  rock,  have  been  cemented  by  opal  and  other 
siliceous  infiltrations  since  their  deposition,  so  that  they  now  form 
brittle  siliceous  masses,  with  pebbles  and  fragments  of  older  rocks 
scattered  through  them.  In  many  places  these  porous  tuffs  and 
breccias  are  richly  charged  with  sulphur,  which  fills  all  the  interstices 
and  sometimes  lines  large  cavities  with  layers  of  crystals  5  or  6  feet 
in  thickness.  In  the  Rabbit-Hole  District  sulphur  has  been  found 
in  quantities  for  a  distance  of  several  miles  along  the  border  of 
the  desert,  but  the  distribution  is  irregular  and  uncertain,  and  is 
always  superficial,  so  far  as  can  be  judged  by  the  present  openings. 
The  sulphur  has  undoubtedly  been  derived  from  a  deeply  seated 
source,  from  which  it  has  expelled  by  heat,  and  escaping  upward 
along  the  lines  of  faulting,  has  been  deposited  in  the  cooler  and 
higher  rocks  in  which  it  is  now  found,  though  whether  the  deposi- 
tion took  place  by  direct  sublimation  or  through  the  decomposition 
of  hydrogen  sulphide  can  not  now  be  told  with  certainty.  Judging 
from  the  siliceous  material  that  cements  the  tuffs,  it  is  evident  that 


ELEMENTS.  19 

the  porous  rocks  in  which  the  sulphur  is  now  found  were  pene- 
trated by  heated  waters  bearing  silica  in  solution  previous  to  the 
deposition  of  the  sulphur.  The  mines  occur  in  a  narrow  north- 
and-south  belt  along  a  line  of  ancient  faulting  which  is  one  of  the 
great  structural  features  of  the  region.  The  absence  of  a  recent 
fault-scarp,  together  with  the  fact  that  the  mines  are  now  cold  and 
do  not  give  off  exhalations  of  gas  or  vapor,  shows  that  the  solfataric 
action  has  long  been  extinct,  though  at  the  Cove  Creek  Mines,  men- 
tioned below,  the  deposition  is  still  in  progress. 

Utah. — Several  sulphur  deposits  occur  in  central  Utah,  in  and 
about  Sulphurdale,  a  small  mining  camp  some  twenty  miles  north 
of  Beaver.  The  best  known  of  these  are  the  Cove  Creek  beds, 
situated  about  four  miles  south  of  Cove  Fort.  The  deposits  have 
been  exploited  in  an  itinerant  way  for  over  thirty  years,  but  their 
full  extent  is  not  as  yet  known.  They  have  been  described  by  G. 
Vom  Rath,1  A.  F.  Du  Faur,2  and  W.  T.  Lee.3 

The  country  is  one  of  late  Quaternary  volcanic  activity,  and  the 
sulphur,  which  is  evidently  due  to  the  oxidation  of  exhalations  of 
hydrogen  sulphide,  occurs  filling  the  interstices  of  volcanic  tuffs — 
in  part  rhyolitic — and  in  horizontal  sheets,  cracks  and  fissures  in 
the  same.  The  material  occurs  in  all  degrees  of  purity,  that  which 
is  worked  varying  from  15  to  85  per  cent  sulphur.  The  average 
output  of  the  region  is  given  as  about  1,000  tons.  Vom  Rath  esti- 
mated the  capacity  of  the  Cove  Creek  deposit  as  some  1,300,000 
tons. 

Sicily. — Of  the  foreign  localities  of  sulphur,  the  most  noted  at 
present  are  those  of  Sicily  and  Japan.  The  first-named  deposits 
are  described  as  occurring  in  Miocene  strata  involving,  from  below 
up,  sandy  marls  with  beds  of  salt,  limy  marls  and  lignite,  gyp- 
sum and  limestone  impregnated  with  sulphur,  black  shales,  and 
micaceous  sands.  Overlying  all  these  is  a  white,  marly  Pliocene 
limestone,  while  below  the  Miocene  is  the  Eocene  nummulitic 
limestone.  The  sulphur  is  found  in  veinlets  and  sometimes  in 


1  Neues  Jahrb.  fur  Min.  u.  Pet.,  I,  1884,  pp.  239-68. 

2  Transactions  of  the  American  Institute  of  Mining  Engineers,  XVI,  1888,  pp.  33-35; 

3  Bulletin  315,  1904,  U.  S.  Geological  Survey,  pp.  485-89. 


20 


THE  NON-METALLIC   MINERALS. 


larger  masses,  which  ramify  through  the  cellular  limestone,  as  shown 
in  Fig.  4. 

The  yield  in  sulphur  varies  from  8  to  25  per  cent,  rarely  running 
as  high  as  40  per  cent.  Below  8  per  cent  the  rock  can  not  be  worked 

economically.  More  or 
less  petroleum  and  bit- 
umen are  found  in  the 
mines.  Barite  and  celes- 
tite  sometimes  accompany 
the  sulphur. 

The  mining  regions 
are  in  the  southern  cen- 
tral portion  of  the  island ; 
Girgenti  and  Larcara  are 
the  chief  centers.  The 
mines  are  distributed  over 
an  area  of  160  to  170 
kilometers  (about  100 
miles)  from  east  to  west, 
and  85  to  90  kilometers 

(55  miles)  from  north  to  south.  They  occur  in  groups  around 
centers,  partly  because  the  sulphur-bearing  stratum  is  not  continu- 
ous, and  partly  because  the  sulphur  indications  are  concealed  by 
later  deposits.  The  region  is  much  faulted. 

Japan.— The  Japanese  sulphur  deposits  are  all  of  volcanic  origin, 
and  the  Abosanobori  Mine,  in  Kxishiro  village,  Kawakami-gori, 
Kushiro  Province,  Hokkaido,  may  be  taken  as  fairly  typical.  The 
mine  is  on  a  conical-shaped  mountain  of  augite  andesite  which,  on 
its  northern  side,  is  open  and  looks  down  upon  a  plain  covered  with 
lava,  and  is  shut  in  by  the  walls  of  the  old  crater  on  the  other  sides. 
Sulphur  is  found  in  different  parts  of  these  walls  in  massive  heaps, 
and  sulphurous  fumes  still  issue  nearly  everywhere  about  the  mines. 
The  ore  as  taken  from  the  mines  carries  from  35  per  cent  to  90  per 
cent  of  sulphur,  which  is  extracted  by  steam  refining  works  at  Hyocha, 
some  35  miles  distant.1 


FIG.   4. — Block  of  limestone    (light)   with  alter 

nating  bands  of  sulphur  (dark).     Sicily. 

[U.  S.  National  Museum.] 


The  Mining  Industry  of  Japan,  by  Wada  Tsunashiro,  1893. 


ELEMENTS.  21 

Other  Japanese  localities  are:  The  Aroya  Mines,  at  Onikobe 
village,  Rikuzen  Province,  and  the  active  volcano  of  Icvo-San,  in 
Yezo. 

In  addition  to  these  localities  may  be  mentioned  the  following, 
In  alphabetical  order:  Austria,  Celebes,  Egypt,  France,  Greece, 
Hawaii,  Iceland,  Italy,  Mexico,  New  South  Wales,  New  Zealand, 
Peru,  Russia,  Spain,  and  the  West  Indies. 

Extraction  and  preparation. — Sulphur  rarely  occurs  in  nature  in 
any  quantity  sufficiently  pure  for  commercial  purposes.  In  freeing 
it  from  its  impurities  three  methods  are  employed:  (i)  Melting, 
(2)  distillation,  and  (3)  solution.  In  the  first  the  ore  is  simply  dry 
roasted  at  a  low  temperature  or  treated  with  superheated  steam 
until  the  sulphur  melts  and  runs  off.  The  process  is  extremely 
wasteful.  A  process  of  fusion  in  a  calcium  chloride  solution  has 
come  into  use  of  late  years,  and  bids  fair  to  yield  better  results  than 
either  of  the  above.  In  the  distillation  process  the  ore  is  heated 
in  iron  retorts  until  the  sulphur  distills  off  and  is  condensed  in 
chambers  prepared  for  it.  The  product  is  mostly  in  the  form  of 
"  flower  of  sulphur."  The  method  is  expensive,  but  the  resultant 
sulphur  very  pure.  In  the  third  process  mentioned  the  ore  is  treated 
with  carbon  disulphide,  which  dissolves  out  the  sulphur  and  from 
which  it  is  recovered  by  evaporation.  This  method,  while  giving 
good  results,  is  also  expensive  and  somewhat  dangerous,  owing  to 
the  explosive  nature  of  the  gases  formed.1 

Uses. — Sulphur  is  used  mainly  for  the  making  of  sulphuric  acid, 
though  small  amounts  are  utilized  in  the  manufacture  of  matches,  for 
medicinal  purposes,  and  in  the  making  of  gunpowder,  fireworks,  in- 
secticides, for  vulcanizing  india  rubber,  etc.  In  the  manufacture  of 
sulphuric  acid  the  sulphur  is  burned  on  a  grate  to  sulphurous  anhy- 
dride (SO  2)  which  is  then  conducted  with  a  slight  excess  of  air  into 
large  lead -lined  chambers  and  mixed  with  steam  and  nitrous  fumes, 
where  the  SO2  is  oxidized  to  the  condition  of  SO3  (sulphuric  anhy- 
dride) and  takes  up  water  from  the  steam,  forming  H2SO4  (sulphuric 
acid).  Ordinary  roll  sulphur  is  quoted  in  the  current  price-lists  at 
from  ij  to  2\  cents  per  pound.  (See  also  under  iron  pyrites,  p.  32.) 

1  The  Mineral  Industry,  II,  1893,  p.  600. 


22  THE  NON-METALLIC  MINERALS. 

BIBLIOGRAPHY. 

R.  PUMPELLY.     Sulphur  in  Japan. 

Geological  Researches  in  China,  Mongolia,  and  Japan.     Smithsonian  Contri« 
butions,  XV,  1867,  p.  n. 
I.  C.  RUSSELL.     Sulphur  Deposits  of  Utah  and  Nevada. 

Transactions  of  the  New  York  Academy  of  Science,  I,  1882,  p.  168. 
A.  FABER  DU  FAUR.     The  Sulphur  Deposits  of  Southern  Utah. 

Transactions  of  the  American  Institute  Mining  Engineers,  XVI,  1887,  p.  33. 
The  Sulphur  Mines  of  Sicily. 

Engineering  and  Mining  Journal,  XL VI,  1888,  p.  174. 
V.  LAMANTIA.     Sulphur  Mines  of  Sicily. 

U.  S.  Consular  Report  No.  108,  1889,  pp.  146-155. 

3.    ARSENIC. 

This  substance  occurs  native  in  the  form  of  a  brittle,  tin-white 
metal,  with  a  specific  gravjty  of  5.6  to  5.7  and  a  hardness  equal  to 
3.5  of  the  scale.  On  exposure  it  becomes  dull  black  on  the  imme- 
diate surface.  It  is  found,  as  a  rule,  in  veins  in  the  older  crystalline 
rocks  associated  with  antimony  and  ores  of  gold  and  silver.  Some 
of  the  more  celebrated  localities  for  the  mineral,  as  given  by  Dana, 
are  the  silver  mines  of  Freiberg,  Annaberg,  Marienberg,  and  Schnee- 
berg  in  Saxony;  Joachimsthal  in  Bohemia;  Andreasberg  in  the 
Harz;  Kapnik  and  Orawitza  in  Hungary;  Kongsberg  in  Norway; 
Zmeiv  in  Siberia;  St.  Maria  aux  Mines,  Alsace;  Mount  Corna 
dei  Darden,  Italy;  Chanarcillo,  Chile;  San  Augustin,  Hidalgo, 
Mexico,  and  New  Zealand.  In  the  United  States  it  has  been  found 
at  Haverhill,  New  Hampshire;  Greenwood,  Maine;  near  Leadville, 
Colorado;  and  on  Watson  Creek,  Frozen  River  in  British  Columbia. 

The  arsenic  of  commerce  is,  however,  rarely  obtained  from  the 
native  mineral,  but  is  prepared  by  the  ignition  of  arsenical  pyrites 
(FeAs2)  or  arsenical  iron  pyrites  (FeS2,FeAs2).  The  white  arsenic 
of  commerce  (arsenious  acid,  As2O3),  though  occurring  sometimes 
native  as  arsenolite  in  the  form  of  botryoidal  and  stalactitic  crusts 
of  a  white  or  yellowish  color,  is,  as  a  rule,  obtained  as  a  by-product 
in  the  metallurgical  operations  of  extracting  certain  metals,  particu- 
larly cobalt  and  nickel,  from  their  ores.  Such  ores  as  Niccolite, 
a  nickel  arsenide  (NiAs),  Gersdorffite  NiAsS),  Rammelsbergite 
(NiAs2),  Smaltite  (CoAs2),  Skutterudite  (CoAs3),  Proustite  (Ag3AsS3), 
and  other  arsenides  and  sulpharsenides  on  roasting  give  up  their 


SULPHIDES  AND  ARSENIDES.  23 

arsenic  in  the  form  of  fumes,  which  are  condensed  in  chambers 
prepared  for  this  purpose. 

Uses. — Arsenic  is  utilized  in  the  form  of  arsenious  acid  (As2O3) 
in  dyeing,  calico  printing,  in  the  manufacture  of  various  pigments, 
in  arsenical  soaps,  in  the  preparation  of  other  salts  of  arsenic,  and 
as  a  preservative  in  museums,  particularly  for  the  skins  of  animals 
and  birds.  See  further  on  p.  32. 


II.  SULPHIDES  AND  ARSENIDES. 

I.    REALGAR  AND  ORPIMENT. 

Realgar  is  a  monosulphide  of  arsenic,  AsS,  =  arsenic,  70.1  per 
cent,  sulphur,  29.9  per  cent.  Hardness,  1.5  to  2;  brittle;  specific 
gravity,  3.55;  color,  aurora-red  to  orange-yellow;  luster,  resinous; 
streak  the  color  of  the  mineral.  Orpiment,  or  auripigment  as  it 
is  also  called,  is  a  trisulphide  of  arsenic  of  the  formula  As2S3,  = 
arsenic,  61  per  cent,  sulphur,  39  per  cent.  Hardness  and  specific 
gravity  essentially  the  same  as  realgar,  with  which  it  is  commonly 
associated. 

Occurrences. — Realgar  and  orpiment  are  very  beautiful,  though 
not  abundant  minerals  which  occur  associated  with  ores  of  silver 
and  lead  in  the  various  mining  regions  of  Japan,  Hungary,  Bohemia, 
Transylvania,  and  Saxony.  They  have  been  reported  in  the  United 
States  in  beds  of  sandy  clay  beneath  lava  in  Iron  County,  Utah, 
and  form  the  so-called  "arsenical  gold  ore"  of  the  Golden  Gate 
Mine,  Mercur,  Tooele  County,  this  same  State,  also  in  San  Bernar- 
dino County,  California;  Douglas  County,  Oregon,  and  in  minute 
quantities  in  the  geyser  waters  of  the  Yellowstone  National  Park. 

The  realgar  and  orpiment  of  the  Coyote  mining  district,  Iron 
County,  Utah,  occur  in  a  compact,  sandy  clay,  occupying  a  horizontal 
seam  or  layer  about  2  inches  thick,  not  distinctly  separated  from  the 
clay,  but  lying  in  its  midst  in  lenticular  and  nodular  masses.  The 
bulk  of  the  layer  consists  of  realgar  in  divergent,  bladed  crystals, 
closely  and  confusedly  aggregated,  sometimes  forming  groups  of 
brilliant  crystalline  facets  in  small  cavities  toward  the  center  of  the 
mass.  The  orpiment  is  closely  associated  with  the  realgar  in  the 


24  THE  NON-METALLIC  MINERALS. 

form  of  small  and  delicately  fibrous  crystalline  rosettes  and  small 
spherical  aggregations  made  up  of  fine  radial  crystals,  and  also  in 
bright  yellow,  amorphous  crusts  in  and  around  the  mass  of  the 
realgar.  Fine  parallel  seams  of  gypsum  occur  both  above  and  below 
the  layer,  and  the  strata  of  arenaceous  clays  above  for  30  feet  or  more 
are  charged  with  soluble  salts  which  exude  and  effloresce  upon  the 
surface  of  the  bank,  forming  hard  crusts.  The  whole  appearance 
and  association  of  the  minerals  indicates  that  they  have  been  formed 
by  aqueous  infiltration  since  the  deposition  of  the  beds.1 

Orpiment  is  said2  to  occur  at  Tajowa,  near  Neusohl,  Hungary, 
as  nodular  masses  and  isolated  crystals  in  clay  or  calcareous  marl. 

Uses. — Realgar  is  used  mainly  in  pyrotechny,  yielding  a  very 
brilliant  white  light  when  mixed  with  saltpeter  and  ignited.  It  is 
now  artificially  prepared  by  fusing  together  sulphur  and  arsenious 
acid.3  Orpiment  is  used  in  dyeing  and  in  preparation  of  a  paste 
for  removing  hair  from  skins.  According  to  the  British  consular 
reports  there  were  exported  from  Baghdad  in  1897,  some  55,600 
pounds  of  the  mineral  for  use  as  a  pigment.  As  with  realgar,  the 
mineral  is  now  largely  prepared  artificially.  The  name  orpiment 
is  stated  by  Dana  to  be  a  corruption  of  aur<,pigment,  golden  paint, 
in  allusion  to  the  color. 

BIBLIOGRAPHY. 

W.  P.  BLAKE.     Occurrence  of  Realgar  and  Orpiment  in  Utah  Territory. 

American  Journal  of  Science,  XXI,  1881,  p.  219. 

H.  B.  FULTON.     Arsenic  in  Spanish  Pyrites,  and  its  elimination  in  the  local  treat- 
ment for  production  of  copper  precipitate. 

Journal  of  the  Society  of  Chemical  Industry,  V,  1886,  p.  296. 
Production  of  Arsenic  in  Cornwall  and  Devon. 

Engineering  and  Mining  Journal,  LII,  1891,  p.  96. 
WILLIAM  THOMAS.     Arsenic. 

The  Mineral  Industry,  II,  1893,  p.  25. 


1  W.  P.  Blake,  American  Journal  of  Science,  XXI,  1881,  p.  219. 
3  H.  A.  Miers,  Mineralogical  Magazine,  July,  1892,  p.  24. 
'Wagner's  Chemical  Technology,  p.  87. 


SULPHIDES  AND  ARSENIDES. 


2.    COBALT   MINERALS. 

Several  minerals  contain  cobalt  as  one  of  their  essential  con- 
stituents in  sufficient  quantity  to  make  them  of  value  as  ores.  In 
other  cases  the  cobalt  exists  in  too  small  quantities  to  pay  for  working 
for  this  substance  alone,  and  it  is  obtained  as  a  by-product  during 
the  process  of  extraction  of  other  metals,  notably  of  nickel.  The 
common  cobalt-bearing  minerals,  together  with  their  chemical  com- 
position, mode  of  occurrence,  and  other  characteristics,  are  given 
below : 

Cobaltite. —  Cobaltine,  or  cobalt  glance.  This  is  a  sulphar- 
senide  of  cobalt  of  the  formula  CoAsS,  =  sulphur,  19.3  per  cent; 
arsenic,  45.2  per  cent;  cobalt,  35.5  per  cent;  hardness,  5.5,  and 
specific  gravity  6  to  6.3.-  The  luster  is  metallic  and  color  silver- 
white  to  reddish.  When  in  crystals,  commonly  in  cubes  or  pyrito- 
hedrons.  Analysis  of  a  massive  variety  from  I,  Siegen,  Westphalia ; 
II,  Skutterud,  Norway,  and  III  and  IV,  Daschkessan,  in  the 
government  of  Elizabethpol,  Caucasus,  as  given  by  various  authori- 
ties, yielded  results  as  below: 


Constituents. 

I. 

II. 

III. 

IV. 

Arsenic.  . 

AC       31 

4?    4.6 

7  £    07 

7.1    7  7 

Sulphur  

JO.  T.X 

20.08 

oo-y/ 

ox  -  16 

Cobalt  

77     71 

77      JO 

1  7    OO 

17    <  ? 

Iron  

I     6* 

32  ? 

I    44 

*  /  -JJ 
Q    8? 

Nickel  

O    22 

y-°5 

o  26 

Undetermined  

4.4.    26 

4O    71 

I 

In  Saxony  the  mineral  occurs  in  lodes  in  gneiss  and  in  which 
heavy  spar  (barite)  forms  the  characteristic  gangue.  It  is  associated 
with  other  metallic  sulphides,  notably  those  of  lead  and  copper.  At 
Skutterud  and  Snarum,  Norway,  the  cobaltiferous  fahlbands,  accord- 
ing to  Phillips,  "  occur  in  crystalline  rocks  varying  in  character  be- 
tween gneiss  and  mica  schists,  but  from  the  presence  of  hornblende 
they  sometimes  pass  into  hornblende  schists ;  among  the  accessory  min- 
erals are  garnet,  tourmaline,  and  graphite.  These  schists,  of  which 


1  Ore  Deposits,  by  J.  A.  Phillips,  p.  389. 


26 


THE  NON-METALLIC  MINERALS. 


the  strike  is  north  and  south,  and  which  have  an  almost  perpendicular 
dip,  contain  fahlbands  very  similar  in  character  to  those  of  Kongs- 
berg.  The  ores  worked  are  cobalt  glance,  arsenical  and  ordinary 
pyrites,  containing  cobalt,  skutterudite,  magnetic  iron  pyrites,  copper 
pyrites,  molybdenite,  and  galena.  Nickel  ores  do  not  accompany 
the  ores  of  cobalt  at  this  locality  in  any  appreciable  quantity.  The 
principal  fahlband  is  known  to  extend  for  a  distance  of  about  6 
miles,  and  is  bounded  on  the  east  by  a  mass  of  diorite  which  pro- 
trudes into  the  fahlband,  while  extending  from  the  diorite  are  small 
dikes  or  branches  traversing  it  in  a  zigzag  course.  It  is  also  inter- 
sected by  dikes  of  coarse-grained  granite  which  contain  no  ore,  but 
which  penetrate  the  diorite." 

The  Skutterud  Mine  in  1879  produced  7,700  tons  of  cobalt  ore, 
which  yielded  108  tons  of  cobalt  concentrates  containing  from  10 
to  ii  per  cent  of  cobalt,  worth  about  ^11,000. 

At  Daschkessan  the  ore  occurs  under  a  sheet  of  diabase,  the 
cobaltite  being  in  the  wall  rock  of  this  sheet,  which  carries  also 
garnets  and  copper  pyrites.  In  1887,  1,216  kilograms  of  the  mineral 
were  extracted;  in  1888,  928  kilograms,  and  in  1889,  12,960  kilograms, 
besides  some  3,000  kilograms  of  cobalti  "erous  matter  obtained  in 
treating  the  cobaltiferous  copper  ores.1 

Smaltite. — This  is  essentially  a  cobalt  diarsenide  of  the  formula 
CoAs2,  =  arsenic,  71.8  per  cent;  cobalt,  28.2  per  cent;  hardness,  5.5 
to  6;  specific  gravity,  6.4  to  6.6.  Color,  white  to  steel-gray.  Through 
the  assumption  of  nickel  the  mineral  passes  by  gradations  into 
chloanthite. 

Analyses  of  samples  from  (I)  Schneeberg,  Saxony,  and  (II)  Gun- 
nison  County,  Colorado,  as  given  by  Dana,  yielded  results  as  below 


Constituents. 

I. 

II. 

Arsenic                                       --• 

71  .  C2 

63.82 

1.38 

I.  CC 

Cobalt                       

l8.07 

II.  SO 

7.?! 

i^-OQ 

Nickel           

1.  02 

Trace. 

O.OI 

0.16 

Annales  des  Mines,  II,  1892,  p.  503. 


SULPHIDES  AND  ARSENIDES.  27 

The  mineral  occurs  like  cobaltite  in  veins  associated  with  other 
metallic  arsenides  and  sulphides. 

The  name  safflorite  is  given  to  a  cobalt  diarsenide  closely  resem- 
bling smaltite,  but  differing  in  being  orthorhombic,  rather  than  iso- 
metric in  crystallization.  The  composition  as  given  by  Dana  is 
quite  variable,  running  from  61  per  cent  to  70  per  cent  arsenic,  and 
10  to  23  per  cent  cobalt,  with  .4  to  18  per  cent  of  iron  and  s,maller 
amounts  of  sulphur,  copper,  nickel,  and  bismuth.  It  is  found 
associated  with  smaltite  in  various  localities. 

Skutterudite  is  the  name  given  to  a  cobaltic  arsenide  of  the 
formula  Co  Ass,  =  arsenic,  79.3;  cobalt,  20.7.  It  is  of  a  tin-white 
color,  varying  to  lead-gray,  has  a  hardness  of  6,  and  specific  gravity 
of  6.72  to  6.86.  It  occurs  associated  with  cobaltite,  titanite,  and 
hornblende  in  a  vein  in  gneiss  at  Skutterud,  Norway. 

Glaucodot  is  a  sulpharsenide  of  cobalt  and  iron  of  the  formula 
(Co,Fe)  AsS,  =  sulphur,  19.4  per  cent;  arsenic,  45.5  per  cent; 
cobalt,  23.8  per  cent;  iron,  11.3  per  cent.  Color,  grayish;  hardness, 
5;  specific  gravity,  5.9  to  6.  Actual  analysis  of  a  Chilean  variety 
yielded  (according  to  Dana)  As  43.2,  S  20.21,  Co  24.77,  Fe  11.90.  It 
is  therefore  essentially  a  ferriferous  cobaltite,  that  is,  a  cobaltite  in 
which  a  part  of  the  cobalt  has  been  replaced  by  iron.  The  mineral 
is  found  at  Huasco,  Chile,  associated  with  cobaltite  in  a  chloritic 
schist.  The  name  allodasite  is  given  to  a  variety  of  glaucodot  con- 
taining bismuth  and  answering  to  the  formula  Co(As,Bi)S.  The 
composition  as  given  is  somewhat  variable.  Arsenic,  28  to  33  per 
cent;  bismuth,  23  to  32  per  cent;  sulphur,  16  to  18  per  cent;  cobalt, 
20  to  24  per  cent;  iron,  2.7  to  3.8  per  cent.  It  is  reported  only 
from  Orawitza,  Hungary. 

Linnaeite  is  a  sulphide  of  cobalt  with  the  formula  Co3S4,  =  sul- 
phur, 42.1  per  cent;  cobalt,  57.9  per  cent;  a  part  of  its  cobalt  is  com- 
monly replaced  by  nickel,  giving  rise  to  its  variety  siegenite.  The 
mineral  is  brittle,  of  a  pale  steel-gray  color,  tarnishing  red.  Hard- 
ness, 5.5  and  specific  gravity,  4.8  to  5.  When  crystallized  it  is  com- 
monly in  octahedrons.  The  following  analyses  of  a  nickel-bearing 
variety  (siegenite)  are  quoted  from  Dana: 


28 


THE  NON-METALLIC  MINERALS. 


Constituents. 

S. 

CO. 

Ni. 

Fe. 

Cu. 

Miisen,  Prussia  

41    OO 

43  86 

Mineral  Hill,  Maryland.  . 
Mine  La  Motte,  Missouri. 

39-70 
41-54 

25.69 
21-34 

29.56 
30.53 

•6L 
1.96 

3.37 

2.23 
Trace. 

The  mineral  occurs  in  gneiss  in  Sweden;  with  barite  and  siderite 
a  Miisen ;  in  limestone  with  galena  and  dolomite  at  Mine  La  Motte, 
Missouri,  and  with  sulphides  of  iron  and  copper  in  chloritic  schists 
in  Maryland. 

Sychnodymite  has  the  formula  (Co,Cu)4S5,  and  yields  sulphur, 
40.64  per  cent;  copper,  18.98  per  cent;  cobalt,  35.79  per  cent; 
nickel,  3.66  per  cent;  iron,  0.93  per  cent.  It  is  of  a  steel-gray  color, 
metallic  luster,  and  has  a  specific  gravity  of  4.75. 

Erythrite  or  cobalt  bloom  is  the  name  given  to  a  hydrous 
cobalt  arsenate  of  the  formula  Co3As2O8+8H2O,  =  arsenic  pentoxide, 
38.4  per  cent;  cobalt  protoxide,  37.5  per  cent,  and  water,  24.1  per 
cent.  It  occurs  in  globular  and  reniform  shapes  and  earthy  masses 
of  a  crimson  to  peach-red  color  associated  with  the  arsenides  and 
sulpharsenides  mentioned  above  and  from  which  it  is  derived  by  a 
process  of  oxidation.  In  Churchill  County,  Nevada,  it  occurs  as 
a  decomposition  product  of  a  cobalt-bearing  niccolite.  It  is  also 
found  at  the  Kelsey  Mine,  Compton,  in  Los  Angeles  County,  Cali- 
fornia; associated  with  cobaltite  at  Tambillo  and  at  Huasco,  Chile, 
and  under  similar  conditions  in  various  parts  of  Europe. 

Asbolite  or  earthy  cobalt,  is  a  black  and  earthy  ore  of  man- 
ganese (wad)  which  sometimes  carries  as  high  as  30  per  cent  of 
cobaltic  oxide.  It  takes  its  name  from  the  Greek  ao-fiohaivca,  to 
soil  like  soot.  Roselite  is  an  arsenate  of  lime,  magnesia,  and  cobalt 
with  the  formula  (Ca,Co,Mg)3As2O8,2H2O,  =  arsenic  pentoxide, 
51.4  per  cent;  lime,  28.1  per  cent;  cobalt  protoxide,  12.5  per  cent; 
water,  8  per  cent.  It  is  of  a  light  to  dark  rose-red  color;  hardness, 
3.5;  specific  gravity,  3.5  to  3.6,  and  vitreous  luster.  Sphaero- 
cobaltite  is  a  cobalt  protocarbonate  of  the  formula  CoCO3,  =  carbon 
dioxide,  37.1  per  cent;  cobalt  protoxide,  62.9  per  cent.  It  is  also  of 
a  rose-red  color,  varying  to  velvet-black.  Hardness,  4,  and  specific 
gravity,  4.02  to  4.13.  It  occurs  but  sparingly,  associated  with  roselite 


SULPHIDES  AND  ARSENIDES. 


29 


at  Schneeberg  in  Saxony.  Remingtonite  is  a  hydrous  carbonate 
the  exact  composition  of  which  nas  not  been  ascertained.  Cobalto- 
menite  is  a  supposed  selenide  of  cobalt.  Bieberite,  or  cobalt 
vitriol,  is  a  sulphate  of  the  formula  CoSO4+7H2O.  The  color  is 
flesh  to  rose-red.  It  is  soluble  in  water,  has  an  astringent  taste, 
and  occurs  in  secondary  stalactitic  form.  Pateraite  is  a  possible 
molybdate  of  cobalt. 

Aside  from  the  possible  sources  mentioned  above,  cobalt  occurs 
very  constantly  associated  with  the  ores  of  nickel  (niccolite,  millerite, 
chloanthite,  etc.),  and  is  obtained  as  a  by-product  in  smelting.  Con- 
siderable quantities  have  thus  from  time  to  time  been  obtained  from 
the  Gap  Mines  of  Pennsylvania,  Mine  La  Motte,  Missouri,  and 
Lovelock,  Nevada.  Certain  gold-copper  mines  in  the  Quartz- 
burg  district,  Grant  County,  Oregon,  are  also  producers.  The 
nickel  mines  of  New  Caledonia  are  perhaps  the  most  pro- 
ductive. The  ore  here,  a  silicate,  carries  some  3  per  cent  of  cobalt 
protoxide. 

A  vein  of  cobalt  ore  near  Gothic,  Gunnison  County,  Colorado', 
is  described  as.  lying  in  granite,  the  gangue  material  being  mainly 
calcite,  throughout  which  was  disseminated  the  ore  in  the  form  of 
smaltite.  With  it  were  associated  erythrite,  a  small  amount  of  iron 
pyrites,  and  native  silver.  An  analysis  of  this  ore  yielded  as  below: 


Cobalt 11-59 

Iron n-99 

Arsenic 63.82 

Silica 2.60 

Lead 2.05 

Sulphur J  •  55 


Bismuth *  •  J3 

Copper o.  16 

Nickel Trace. 

Silver Trace. 

94.89 


A  cobalt  ore,  consisting  of  a  mixture  of  glaucodot  and  erythrite, 
occurring  near  Carcoar  Railway  Station,  New  South  Wales,  has  the 
composition  given  below: 


3° 


THE  NON-METALLIC  MINERALS. 


Constituents. 

I. 

II- 

T^oisture  ... 

1  20 

2     1  80 

Metallic  arsenic.  ... 

r  i    8lO 

2O    OIO 

Metallic  cobalt  .                 ... 

jo  4.4.7 

I  3    S^O 

Metallic  nickel.  .  . 

t;oo 

•5QO 

Metallic  iron.  .....    .....    .    .        .    . 

ii  860 

•jy~ 

jc    78 

Alumina                    .    .......    .    ...    .    . 

Trace. 

Metallic  manganese.  ...  .............. 

Nil. 

Nil. 

Metallic  calcium.  ................    ... 

Nil. 

71 

M^a^nesium       .    ..................... 

i  480 

.  22 

Gold      .           

Trace. 

Silver.  ..   .    ......................... 

Trace. 

I     Z2O 

II    24 

Gangue  (insoluble  in  acids)   . 

22    O78 

26    ^1 

Totals  ,. 

99.905 
c  .4? 

99.67 

According  to  the  Annual  Report,  Department  of  Mines,  for 
1888,  this  ore  occurs  concentrated  in  irregular  hollows  and  bunches, 
often  intimately  mixed  with  diorite  in  a  line  of  fissure  between  an 
intrusive  diorite  and  slate,  the  fissure  running  for  some  distance  follow- 
ing the  line  of  junction  between  the  two  rocks,  and  being  presumably 
formed  at  the  time  of  the  extrusion  of  the  diorite. 

Other  cobalt  ores,  carrying  from  13  to  15  per  cent  of  cobalt  oxide, 
occur  near  Nina.1 

Uses. — Cobalt  is  produced  and  sold  in  the  form  of  oxide  and 
used  mainly  as  a  coloring  constituent  in  glass  and  earthern  wares. 
Only  some  200  tons  are  produced  annually  the  world  over.  The 
market  value  of  the  material  is  variable,  but  averages  about  $2  a 
pound. 

BIBLIOGRAPHY. 
FUCHS  erDE  LAUNAY.     Traite  des  Gites  Mineraux,  II,  pp.  75-91. 

3.    ARSENOPYRITE ;   MISPICKELJ   OR   ARSENICAL   PYRITES. 

Composition. — Somewhat  variable.  Essentially  a  sulpharsenide 
of  iron  of  the  formula  FeAsS,  or  FeS2,  FeAs2,  =  arsenic,  46  per  cent ; 
sulphur,  19.7  per  cent,  and  iron,  34.3  per  cent.  The  name  danaite 
is  given  to  a  cobaltiferous  variety.  The  specific  gravity  of  the  mineral 


Complete  analyses  of  these  are   given  in  Catalogue  of  the  New  South   Wales 
Exhibit,  World's  Columbian  Exposition,  Chicago,  1893,  p.  330. 


SULPHIDES   AND   ARSENIDES. 


varies  from  5.9  to  6.2.     Hardness,  5.5  to   6.     Colors,   silver-white 
to  steel-gray;  streak,  dark  gray  to  black;  luster,  metallic.     Brittle. 
Occurrence  and  uses. — See  under  Lollingite. 


4.  LOLLINGITE;   LEUCOPYRITE. 

The  prismatic  arsenical  pyrites,  or  leucopyrite,  is  essentially  a 
diarsenide  of  iron,  with  the  formula  FeAs2,  though  usually  contami- 
nated with  a  little  sulphur  and  not  infrequently  cobalt,  bismuth,  or 
antimony.  It  has  a  specific  gravity  of  7  to  7.4,  hardness  of  5  to  5.5, 
metallic  luster,  and  silver-white  to  steel-gray  color.  Either  lollingite 
or  arsenopyrite  can  be  readily  recognized  by  the  strong  odor  of 
garlic  given  off  when  roasted. 

Occurrence  and  uses. — Arsenopyrite  and  lollingite  both  occur 
commonly  in  crystalline  rocks  and  associated  with  other  metallic 
arsenides  and  sulphides,  and  with  ores  of  gold,  silver,  tin  and  lead. 
Mispickel  is  itself  at  times  highly  auriferous  and  forms  a  valuable 
ore  of  gold  as  in  New  South  Wales,  California  and  Alaska.  Both 
minerals,  often  associated  with  the  alteration  product  scorodite, 
occur  in  veins  intersecting  the  older  crystalline  rocks  in  Orange, 
Putnam  and  Essex  counties,  New  York.  Near  Kent,  in  Putnam 
County,  the  vein  is  in  gneiss  and  consists  of  a  white  quartz  gangue 
with  varying  proportions  of  the  arsenide  and  iron  pyrites.  It  has 
a  northerly  strike,  and  is  in  close  proximity  and  runs  parallel  with  a 
dike  of  basic  igneous  rock,  though  there  is  no  apparent  connection 
between  the  two.  Hand-sorted  samples  of  this  ore  yielded : 


Constituents. 

Per  Cent. 

Silica        (SiO2)  

2.90 

Iron          (Fe) 

T.6    II 

Copper     (Cu) 

2    17 

Sulphur   (S) 

22    72 

Arsenic    (As) 

^6    OO 

Total 

00-  CO 

Near  Edenville  and  in  other  places  in  Orange  County,  arsenopy- 
rite— associated  with  leucopyrite  and  the  hydrous  arsenate  scoro- 
dite— occurs  in  crystalline  limestone.  Near  Christiansburg,  Mont- 


32  THE  NON-METALLIC  MINERALS. 

gomery    County,    Virginia,    granular    mispickel    occurs    intimately 
associated  with  iron  pyrites  in  quartz  schist. 

That  these  arsenides  could  be  utilized  as  sources  of  arsenic  is 
apparent.  As  a  matter  of  fact,  however,  a  very  large  portion  of 
the  arsenic  of  commerce  is  obtained  as  a  by-product  in  the  smelting 
of  arsenical  ores  of  gold,  silver,  copper,  etc.,  and  still  larger  quanti- 
ties might  thus  be  obtained — more,  indeed,  than  the  market  demands 
— did  smelters  arrange  to  condense  and  save  the  fumes  from  their 
smelters.  It  has  been  stated  that  from  the  stacks  of  the  Washoe 
smelter  (at  Anaconda,  Montana)  there  escaped  during  each  day  of 
August,  1905,  some  57,270  pounds  of  arsenic;1  in  fact,  that  from 
this  smelter  alone  the  waste  arsenic  at  that  time  exceeded  six  times 
the  entire  domestic  output.  In  spite  of  these  abundant  sources  of 
supply  in  the  western  mining  regions,  proximity  to  market  and 
other  advantages  have  favored  a  moderate  development  elsewhere. 
In  Putnam  County,  New  York,  ore  from  a  lode  varying  from  12  to 
20  feet  in  width  is  mined  and  from  it  a  product  obtained  averaging 
25  per  cent  of  metallic  arsenic.  Recent  developments  have  also 
been  made  in  the  Virginia  deposit  noted.  Aside  from  that  of  the 
white  arsenic  of  the  druggists  the  material  appears  in  the  market  in 
form  of  a  variety  of  salts  and  industrial  preparations,  as  Sheep  dip, 
Paris  Green,  London  Purple,  etc.  Some  1,700  long  tons  of  white 
arsenic  were  produced  in  this  country  in  1907  and  5,000  tons  im- 
ported. 

5.  PYRITES. 

Two  forms  of  the  disulphide  of  iron  are  common  in  nature. 
The  first,  known  simply  as  pyrite  or  iron  pyrites,  occurs  in  sharply 
defined  cubes  and  their  crystallographic  modifications,  or  in  granular 
masses  of  a  brassy-yellow  color. 

The  second,  identical  in  composition,  crystallizes  in  the  orthorhom- 
bic  system,  but  is  more  common  in  concretionary,  botryoidal,  and 
stalactitic  forms,  which  are  of  a  dull  grayish-yellow  color.  This  form 
is  known  as  marcasite  or  gray  iron  pyrites.  Both  forms  have  the 

1  Journal  of  American  Chemical  Society,  XIX,  1907. 


SULPHIDES  AND  ARSENIDES. 


33 


chemical  composition,  FeS2,  =  iron,  46.6  per  cent  and  sulphur,  53.4 
per  cent. 

The  ore  as  mined  is,  however,  never  chemically  pure,  but  con- 
tains admixtures  of  other  metallic  sulphides,  besides,  at  times,  con- 
siderable quantities  of  the  precious  metals.  The  following  analyses1 
of  materials  from  well-known  sources  will  serve  to  show  the  general 
variation : 


Constituents. 

I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

Sulphur.       .    ... 

48.0 

48.0 

48.02 

40.00 

47.76 

46.40 

45.60 

Iron.  .       

4VO 

44.0 

42.01 

3^  -OO 

43-99 

30.00 

38.552 

i  6 

i  6 

400 

3-69 

I     ^O 

I       !? 

I    c 

0.24 

6  oo 

Silica  

c  .0 

a.  7 

7.6o 

20.00 

1.99 

9.2c; 

8.70 

Alumina, 

3   7C 

Trace. 

Trace. 

o  83 

O    IO 

Trace. 

Silver  and  gold 

Trace. 

Trace. 

Lead 

o.  10 

o  64 

I.  Milan,  Coos  County,  New  Hampshire;  II.  Rowe,  Massachusetts;  III.  Louisa 
County,  Virginia;  IV.  Sherbrooke,  Canada;  V.  Rio  Tinto,  Spain;  VI.  near  Lyons, 
France;  VII.  Westphalia,  Germany. 

Pyrite  is  sufficiently  hard  to  scratch  glass,  and  this,  together  with 
its  color,  crystalline  form,  and  irregular  fracture,  is  sufficient  for 
its  ready  determination  in  most  cases.  Once  known,  it  is  thereafter 
readily  recognized.  Owing  to  its  yellow  color,  the  mineral  has  by 
ignorant  persons  been  mistaken  not  infrequently  for  gold — which, 
however,  it  does  not  at  all  resemble — and  has  hence  earned  the  not 
very  flattering  but  quite  appropriate  name  of  "fool's  gold."  In 
certain  cases,  however,  it  carries  the  precious  metals,  and  in  many 
regions  is  sufficiently  rich  in  gold  to  form  a  valuable  ore. 

Mode  of  occurrence  and  origin. — Pyrite  is  one  of  the  most  widely 
disseminated  of  minerals,  both  geologically  and  geographically, 
occurring  in  rocks  of  all  kinds  and  of  all  ages  the  world  over.  It  is 
found  in  the  form  of  disseminated  grains  throughout  the  mass  of  a 
rock,  or  along  the  line  of  contact  between  basic  eruptives  and  sedi- 
mentaries;  as  irregular  and  sporadic  and  concretionary  masses  in 
sedimentary  rocks  and  modern  sands  and  gravels;  in  the  form  of 


1  Mineral  Resources  of  the  United  States,  1883-1884,  p.  877. 


34  THE  NON-METALLIC  MINERALS. 

true  fissure  veins,  and  as  interbedded,  often  lenticular  masses, 
sometimes  of  immense  size,  lying  conformably  with  the  strat- 
ification (or  foliation)  of  the  inclosing  rock.  On  the  immediate 
surface  the  mineral  is  in  most  cases  considerably  altered 
by  oxidation  and  hydration,  forming  the  caps  of  gossan  or 
limonite. 

The  origin  of  the  mineral  in  the  older  crystalline  rocks, 
as  that  of  the  rocks  themselves,  is  not  infrequently  somewhat 
obscure.  In  sedimentary  rocks  it  is  undoubtedly  due  to  the 
precipitation  of  the  included  ferruginous  matter  by  sulphureted 
and  deoxidizing  solutions  from  decomposing  animal  and  vegetable 
matter. 

At  the  Stella  mine,  DeKalb  Junction,  St.  Lawrence  County, 
New  York,  the  country  rock  is  a  light  gray  gneiss,  the  well-marked 


FIG.  5. — Plan  of  pyrite  lens,  Louisa  County,  Virginia,     (a)  Pyrite;  (&)  schist. 
[After  Thos.  Watson,  Mineral  Resources  of  Virginia.] 


foliation  showing  a  strike  of  N.  20°  to  30°  E.,  and  dipping  20°  to 
30°  to  the  northwest.  It  is  probably  a  sheared  igneous  rock  of 
pre-Cambrian  age.  At  the  mine  the  gneiss  incloses  a  band  of  fine- 
grained, dark-colored  schist  15  to  20  feet  in  width.  This  is  also 
regarded  as  an  altered  igneous  rock  intrusive  in  the  gneiss.  The 
pyrite  occurs  in  a  series  of  overlapping  lenses  in  this  schist. 
These  may  vary  from  200  to  250  feet  in  length,  with  an  average 
thickness  of  12  feet.  The  lump  ore,  as  shipped,  carries  some 
35  per  cent  of  sulphur.  The  average  mill  ore  carries  but  some  27 
per  cent,  which  amount  is  brought  up  to  44  or  45  per  cent  by 
careful  concentration. 

Pyrite  outcroppings  are  found  in  Louisa  and  Prince  William 
counties,  Virginia,  over  an  area  some  two  miles  in  length.  The  ore 
occurs  in  the  form  of  lenses  (see  Figs.  5  and  6),  often  of  large  size, 


SULPHIDES  AND  ARSENIDES. 


35 


in  crystalline  schists,  the  largest  thus  far  reported  in  Louisa  County 
being  700  feet  in  length  with  a  maximum  thickness  of  60  feet,  and  in 
Prince  William  County,  1,000  feet  in  length  with  a  width  of  10  feet. 
They  are  stated  l  by  Watson  to  conform  in  dip  and  strike  with  the 
schists,  which  in  Louisa  County  is  60°  to  65°  to  the  southeast,  and 
north  10°  to  20°  east;  for  Prince  William  County  the  dip  is  25° 
to  55°  to  the  northwest,  the  strike  remaining  the  same.  The  contact 
between  the  ore  bodies  and  the  country  rock  is  described  as  unusually 
sharp,  though  occasional  gradations  are  met  with.  Thin  layers 
of  grayish  white  limestone  often  occur  interlaminated  with  the 
schists  and  sometimes  in  close  juxtaposition  with  the  ore  bodies. 


FIG.  6. — Section  showing  stringers  of  pyrite  (a)  interleaved  with  schist  (6). 
[After  Thos.  Watson,  Mineral  Resources  of  Virginia.] 


Dr.  Watson  is  disposed  to  regard  the  pyrite  as  having  originated 
through  a  process  of  replacement  of  some  of  these  limestone  bodies 
by  sulphides. 

The  ore  is  massive  and  consists  of  fine,  and,  at  times,  very  compact 
aggregates  of  granular  pyrite.  As  mined  it  averages  from  43  to  45 
per  cent  sulphur. 

At  Rio  Tinto,  Spain,2  the  ore  is  described  as  occurring  in  immense 
masses  several  thousand  feet  in  length,  and  from  300  to  800  feet 
in  width,  extending  in  depth  to  an  unknown  distance.  The 
ore  is  very  clean  and  massive,  containing  besides  sulphur  and 
iron  only  some  2  to  4  per  cent  of  copper  and  traces  of  silver 
and  gold.  The  material  is  mined  wholly  from  open  cuts  and 


1  Mineral  Resources  of  Virginia,  p.  190. 

2  A  Visit  to  the  Pyrites  Mines  of  Spain,  Eng.  and  Min.  Jour.,  LVI,  1893,  p.  498. 


36  THE    NON-METALLIC  MINERALS. 

to  a  depth  of  some  400  feet.  The  country  rock  is  described 
as  of  Silurian  and  Devonian  schists,  the  ore  occurring  near 
contact  with  diorites. 

Uses. — With  the  exception  of  the  small  amount  utilized  in 
the  preparation  of  vermilion  paints  almost  the  sole  value  of 
the  pyrite  is  for  the  manufacture  of  sulphuric  *icid  and  the 
sulphate  of  iron,  known  as  green  vitrol  or  copperas.  In  the 
process  of  making  sulphuric  acid  the  ore  is  roasted  or  burnt 
in  specially  designed  ovens  and  furnaces  until  the  mineral  is  de- 
composed, the  sulphur  fumes  being  caught  and  condensed  in 
chambers  prepared  for  the  purpose.  By  the  Glover  and  Gay- 
Lussac  method  from  280  to  290  parts  of  sulphuric  acid  of  a 
density  of  66°  Baume  may  be  obtained  for  each  100  parts  of  sul- 
phur in  the  ore,  or  about  2,565  pounds  of  acid  to  one  ton  (2,000 
pounds)  of  average  ore. 

According  to  F.  Stolba,1  the  so-called  Bohemian  fuming  sul- 
phuric acid  is  made  from  vitriol  obtained  from  Silurian  pyritiferous 
schists  (" vitriolschief er ") .  The  method  as  given  is  as  follows: 
Large  masses  of  the  schist,  which  consist  essentially  of  a  quartzose 
matrix  containing  pyrite,  carbonaceous  matter,  and  clay,  are  exposed 
to  the  weathering  action  of  the  atmosphere  for  three  years.  The 
products  of  oxidation  so  formed  are  ferrous  sulphate  and  sulphuric 
acid,  which  latter  acts  energetically  upon  the  clay,  and  finally  alu- 
minum sulphate  and  other  sulphates  are  yielded.  The  ferrous  sul- 
phate at  first  formed  becomes  by  oxidation  ferric  sulphate,  which, 
together  with  the  aluminum  sulphate,  is  the  principal  product  of 
the  weathering  of  the  vitriol  slate.  Ferrous  sulphate  remains  only 
in  small  quantities.  The  next  operation  is  lixiviation  of  the  mass 
with  water,  after  which  the  liquor  obtained  is  concentrated  to  a 
density  of  40°  Baume,  and  finally  evaporated  in  pans  until,  on 
cooling,  a  crystalline  cake  of  vitriol  stone  is  obtained,  The  vitriol 
stone  is  now  calcined  in  order  to  remove  the  greater  part  of  its  water. 
The  resulting  product,  when  heated  to  a  very  high  temperature  in 
clay  retorts,  yields  sulphuric  anhydride,  and  a  residue,  termed 

1  Journal  of  the  Society  of  Chemical  Industry, V,  1886,  p.  30. 


SULPHIDES  AND  ARSENIDES.                                    37 

colcothar,  remains  in  the  retorts.     The  composition  of  vitriol  stone 
and  colcothar  will  be  seen  from  the  following  analyses  :  1 

VITRIOL  STONE.  VITRIOL  STONE. 

Fe2O3  ................   20.07  Fe2(SO4)3  ..............   S0-1? 

A1203  .................     4-67  A12(S04)3  ...............   11.94 

FeO  ..................     0.64  FeSO4  .................     1.35 

MnO  ................  Traces.  MgSO4  ......  ...........     1.17 

CaO  ..................     0.14  CaSO4  .................     0.33 

MgO  ..............  ____     °-39  CuSO4  .................     0.20 

K20  ..................     0.07  K2S(>4  .................     0.13 

Na20  .................     0.05  Na2SO4  ................     o.n 

CuO  .................     o.io  H2SO4  .................     1.49 

SiO2  ..................     o.io  MnO,  As,  and  P2O5  ...  .Traces. 

P2O5  ................  Traces.  SiO2  ...................     9.10 

SO3  ..................  4Q-51  H2°  ...................   32.31  =  99.29 

As  ...................  Traces, 


COLCOTHAR. 

Fe2O3  ................  74-62  SO3  ....................  5.17 

\12O3  .................  12.53  SiO2  ...................  1.17 

MgO  .................  3.23  CuO  ...................  0.20 

•CaO  ..................  0.82  H20  ...................  1.30  =  99.04 

Pyrite  on  decomposing  in  the  presence  of  moisture  in  the  ground 
sometimes  gives  rise  to  an  acid  sulphate  of  iron.  This  may  attack 
aluminous  minerals  when  such  are  present,  giving  rise  thus  to  solutions 
of  sulphate  of  iron  and  alumina,  which  come  to  the  surface  as  "  alum 
springs,"  or,  if  no  alumina  is  present,  merely  as  iron  or  chalybeate 
springs,  which  are  of  more  or  less  medicinal  value.  The  presence 
of  such  sulphates  in  a  soil  is  readily  detected  by  the  well-known 
astringent  taste  of  green  vitriol  and  alum,  even  where  the  quantity 
is  not  sufficient  to  appear  as  a  distinct  efflorescence.  Impregnation 
of  these  salts  in  soils  are  by  ignorant  persons  sometimes  assumed 
to  be  of  great  medicinal  value,  and  the  writer  has  in  mind  a  case 
in  one  of  the  Southern  States,  in  which  the  aqueous  leachings  of  such  a 
soil  were  regularly  bottled  and  sold  as  a  specific  for  nearly  all  the 
ills  to  which  the  flesh  is  heir,  though  prescribed  especially  for  flux, 
wounds,  and  ulcers.  (See  also  under  Alum,  p.  350.) 

In  the  manufacture  of  copperas  the  ore  is  broken  into  small  pieces 
and  thrown  into  piles  over  which  water  is  allowed  to  drip  slowly.  A 

1  The  Geology  of  England  and  Wales,  p.  279. 


THE  NON-METALLIC  MINERALS. 


natural  oxidation  takes  place,  whereby  the  sulphide  is  transformed 
into  a  hydrated  sulphate.  The  latter  being  soluble,  runs  off  in 
solution  in  the  water,  which  must  be  collected  and  evaporated  in  order 
to  obtain  the  salt.  Thus  prepared  the  sulphate  is  used  in  dyeing, 
in  the  manufacture  of  writing-ink,  as  a  preservative  for  wood,  and  as 
a  disinfectant.  It  has  also  been  used  in  the  manufacture  of  certain 
brands  of  fertilizers. 

The  analysis  given  below  show  (i)  the  composition  of  fresh 
pyrite  from  the  Coal  Measures  of  Mercer  County,  Pennsylvania, 
and  (2)  and  (3)  that  of  two  varieties  of  paint  produced  from  it  by 
calcination.1 


Constituents. 

I. 

II. 

III. 

Bisulphide  of  iron  

96.  161 

o  4.15; 

o  40^ 

Bisulphide  of  copper  

Trace. 

Sesquioxide  of  iron 

66  143 

77     Id.  3 

Alumina                                  , 

6^3 

60  7 

CA-l 

Protoxide  of  iron  

6.  300 

$  •  142 

.4^0 

.160 

.160 

^Magnesia 

1  4O 

IOO 

IOO 

Silica. 

680 

3  880 

7      080 

Sulphuric  acid 

13   1  10 

7    334 

\Vater  and  carbonaceous  matter 

0    10  "?  ; 

5104 

Undetermined.  .       

I    Ql6 

Total  

IOO.OOO 

IOO.OOO 

I  OO  .  OOO 

6.  PYRRHOTITE:  MAGNETIC  PYRITES. 

This  form  of  iron  sulphide  differs  from  either  of  the  pyrites  just 
described  not  merely  in  the  relative  proportions  of  sulphur  and  iron, 
but  in  its  bronze  color  and  property  of  being  attracted  by  the  magnet. 
Moreover  it  does  not  show  the  cubic  crystal  forms  of  pyrite  and  in- 
deed is  rarely  found  in  crystals  at  all. 


1  Report  M.  M.  Second  Report  of  Progress  in  the  Laboratory  of  the  Survey  at 
Harrisburg,  Second  Geological  Survey  of  Pennsylvania,  1879,  p.  374. 


SULPHIDES   AND  ARSENIDES.  39 

The  content  in  sulphur  (38  to  39  per  cent)  is  too  small  to  make 
it  of  immediate  value  in  the  manufacture  of  sulphuric  acid.  It  is 
stated,  however,  that  in  certain  cases,  as  at  the  Sudbury  nickel  mines 
where  the  mineral  occurs  so  closely  associated  with  ores  of  other 
metals  as  to  necessitate  a  common  treatment  for  all,  the  sulphurous 
fumes  from  the  roasters  can  be  economically  condensed  and  utilized 
in  the  ordinary  way.  It  is  a  safe  prediction  that  in  the  not  very 
distant  future  the  mineral  must  be  utilized  as  an  ore  of  iron. 


BIBLIOGRAPHY. 

W.  H.  ADAMS.     The  Pyrites  Deposits  of  Louisa  County,  Virginia. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XII,  1883,  p.  527. 
WILLIAM  MARTYN.     Pyrites. 

Mineral  Resources  of  the  United  States,  1883-84,  p.  877. 
J.  H.  COLLINS.     The  Great  Spanish  Pyrites  Deposits. 

Engineering  and  Mining  Journal,  XL,  188^,  p.  79. 
E.  D.  PETERS.     A  Visit  to  the  Pyrites  Mines  of  Spain. 

Engineering  and  Mining  Journal,  LVI,  1893,  p.  498. 
FRANK  L.  NASON.     Origin  of  the  Iron  Pyrites  Deposits  in  Louisa  County,  Virginia. 

Engineering  and  Mining  Journal,  LVII,  1894,  p.  414. 
M.  DRILLON.     The  Pyrites  Mines  of  Sain-Bel. 

Minutes  of  Proceedings  of  the  Institute  of  Civil  Engineers,  CXIX,  1894-95, 
p.  470. 


7.    MOLYBDENITE. 

This  is  a  disulphide  of  molybdenum  having  the  formula  MoS2,  = 
sulphur,  40  per  cent;  molybdenum,  60  per  cent. 

The  mineral,  like  graphite,  occurs  in  black,  shining  scales, 
sometimes  hexagonal  in  outline  and  with  a  bright  metallic  luster. 
It  is  soft  enough  to  be  readily  impressed  with  the  thumb  nail,  and 
leaves  a  bluish-gray  trace  on  paper.  On  procelain  it  leaves  a  lead- 
gray,  slightly  greenish  streak.  This  faint  greenish  tinge,  together 
with  its  property  of  giving  a  sulphur  reaction  when  fused  with  soda, 
furnishes  a  ready  means  of  distinguishing  it  from  graphite,  which 
it  so  closely  resembles.  Through  alteration  it  sometimes  passes 


40  THE  NON-METALLIC  MINERALS. 

over  into  molybdite  or  molybdic  ocher,  a  straw-yellow  to  white 
ocherous  mineral  of  the  formula  MoC>3,  =  oxygen,  33.3  per  cent; 
molybdenum,  66.7  per  cent. 

Occurrence. — The  mineral  has  a  wide  distribution,  occurring  in 
embedded  masses  and  disseminated  scales  in  granite,  gneiss,  syenite, 
crystalline  schists,  quartz,  and  granular  limestone.  It  is  found  in 
Norway,  Sweden,  Russia,  Saxony,  Bohemia,  Austria,  France,  Peru, 
Brazil,  England,  and  Scotland,  throughout  the  Appalachian  region 
in  the  United  States  and  Canada,  and  in  various  parts  of  the  Rocky 
and  Sierra  Nevada  Mountains.  In  Okanogan  County,  Washington, 
the  mineral  occurs  in  beautiful  large  flakes  in  an  auriferous  quartz 
vein  transversing  slates. 

At  Crown  Point,  in  Chelan  County,  this  same  State,  molybdenite 
occurs  in  a  nearly  horizontal  quartz  vein  cutting  a  gray  biotite  granite, 
the  mineral  itself  being  in  the  form  of  crystals  and  flakes  20  mm. 
or  more  in  diameter,  and  in  small  seams  extending  through  the 
quartz  in  all  directions.1  In  British  Columbia  it  has  been  reported  2 
as  occurring  in  massive  veins  sometimes  8  inches  in  width.  At 
Cooper,  Washington  County,  Maine,  the  mineral  is  found  in  dikes 
of  pegmatite  cutting  granite  and  also  in  the  granite  itself  adjacent  to 
the  dikes.  The  pegmatites,  in  this  instance  are  regarded  as  approx- 
imately contemporaneous  with  the  granite,  representing  the  latest 
crystallization  of  the  granitic  magma,  and  the  molybdenum  sulphide, 
an  original  constituent  of  the  magma,  crystallizing  early  during  the 
process  of  cooling.3 

On  Quetachoo-Manicouagan  Bay,  on  the  north  side  of  the  Gulf 
of  St.  Lawrence,  the  mineral  is  reported  4  as  occurring  disseminated 
in  a  bed  of  quartz  6  inches  thick,  in  the  form  of  nodules  from  i  to  3 
inches  in  diameter,  and  in  flakes  which  are  sometimes  12  inches 
broad  by  i  inch  in  thickness.  It  is  also  found  in  the  form  of  finely 
disseminated  scales  or  small  bunches  among  the  iron  ores  of  the 
Hude  Mine  at  Stanhope,  New  Jersey,  sometimes  constituting  as 
high  as  2  per  cent  of  the  ore. 

1  A.  R.  Crook,  Bulletin  Geological  Society  of  America,  XV,  1904,  p.  283. 

2  Journal  Canadian  Mining  Institute,  VII,  1904,  p.  164. 

3  G.  O.  Smith,  Bulletin  26,  U.  S.  Geological  Survey,  1904,. p.  198. 

4  Geology  of  Canada,  1863,  p.  754. 


SULPHIDES  AND  ARSENIDES.  41 

Molybdenum  is  also  a  constituent  of  the  mineral  wulfenite,  or 
molybdate  of  lead. 

Uses. — The  principal  use  to  which  molybdenite  has  as  yet  been 
put  is  in  the  preparation  of  molybdates  for  the  chemical  laboratory. 
It  is  stated  that  a  fine  blue  pigment  can  be  prepared  from  it,  which 
it  has  been  proposed  to  use  as  a  substitute  for  indigo  in  dyeing  silk, 
cotton,  and  linen.  The  metal  molybdenum  is  produced  but  rarely, 
and  only  as  a  curiosity,  and  has  a  purely  fictitious  value.  Up  to 
the  present  time  there  has  been  no  constant  demand  for  the  mineral 
nor  regular  source  of  supply. 


8.  PATRONITE:  VANADIUM  SULPHIDE. 

The  name  patronite  or  Rizo-patronita  has  recently  (1906)  been 
applied  to  a  peculiar  amorphous  asphaltic-appearing  material, 
nearly  black  in  color,  breaking  with  a  smooth  to  uneven  and  irregular 
fracture  and  which  analyses  show  to  be  essentially  a  vanadium  sul- 
phide, though  in  nature  almost  universally  admixed  with  silica, 
alumina,  iron  oxides  and  other  impurities. 

Composition. — The  composition  of  the  crude  material  as  given 
bv  different  authorities  is  as  below: 


Constituents. 

I 

II. 

III. 

SiO,.. 

10.88 

6  88 

22    22 

A12O,  

3.8<; 

2    OO 

8    32 

Fe  

2    A=t 

2    Q2 

I    08 

V  

16  08 

IQ    c? 

j..yo 
ir    36 

MoO,  .  . 

o  so 

xyoo 
o  18 

S  soluble  in  CS2  

6  cc 

4   "?O  ) 

S  (combined)  

£4  06 

^  ~>      V 
^4   2Q  I 

4I.8I 

CaO  

o  33 

Moisture  

Trace 

I    OO 

Undetermined 

c  61  l 

9  88  2 

100.00 

92.20  3 

100.00 

i.  Largely  carbonaceous,     a.  Carbon.     3.  Contained  also  Ni,   1.87;    C,  3.47;    TiO2,   1.53; 

,    0.20. 


The  formula  for  the  minerals  as  suggested  by  these  analyses  is 
somewhat  uncertain,  but  may  be  ¥84.     With  the  patronite  occurs  an 


42  THE  NON-METALLIC  MINERALS. 

asphaltic  compound,  to  which  the  name  Quisqueite  has  been  given; 
a  coke-like  material  yielding  some  86.63  Per  cent  ^ree  carbon;  a 
little  free  sulphur;  an  iron-nickel  sulphide  and  the  impurities  noted 
in  the  analyses. 

Occurrence. — Although  vanadium-bearing  hydrocarbons  are  not 
uncommon,  material  o'f  the  composition  and  character  indicated  has 
thus  far  been  reported  only  from  Minasragra,  some  46  kilometers 


-  Magnetic  North 
True  North 


Limit  of  Alteration 
and  Oxidized  Ores 
Present  Limit 


Surface  Limit  of  Alteration 
and  Oxidized  Ores 


TRENCH  A  /  |  Probable  surface 

/     TRENCH  B\  position  of  Fault 

•Surface  Limit  of  Alteration 

and  Oxidized  Ores  TRENCH  G I 


Vein 
Sulphide 


Altered  Shale 
Vanadium  Vein 


FIG.  7. — Map  of  La  Quimira  patronite  area,  Minasagra,  Peru. 
[After  D.  F.  Hewett,  Bulletin  American  Institute  of  Mining  Engineers,  1909.] 

from  Cerro  de  Pasco  in  Peru.  The  region  is  one  occupied  by  Jura- 
trias  and  Cretaceous  shales,  sandstones,  and  limestones  dipping 
toward  the  northeast,  much  faulted  and  injected  by  dikes  of  trachyte, 
andesite,  dolerite,  diabase,  and  quartz  porphyry.  The  entire  vana- 
dium-bearing deposit  consists  of  a  lens-shaped  mass  occupying  one 
of  the  faults.  The  maximum  width  is  some  28  feet  and  the  length,  so 
far  as  ascertained,  350  feet,  with  a  strike  N.  20°  W.,  and  dip  of  75°  W. 
This  lens-shaped  mass  is  composed  mainly  of  three  constituents, 
(i)  quisqueite,  a  black,  lustrous  hydrocarbon  of  a  hardness  of  4.5 
and  specific  gravity  of  1.75;  (2)  a  dull  black,  coke-like  hydrocarbon 


MAUDES.  43 

of  a  hardness  of  4.5  and  specific  gravity  of  2.4;  and  (3)  the  patronite. 
The  relative  position  of  these  is  shown  in  Fig.  7. 

Origin. — No  satisfactory  explanation  of  this  deposit  is  as  yet  at 
hand.  Very  probably  the  entire  deposit  may  have  been  formed  as 
have  other  asphaltic  vein  masses  in  Utah  and  elsewhere,  i.e.,  the 
material  was  forced  into  the  shales  while  in  a  plastic  condition. 
It  is  conceivable,  writes  Hillebrand,  that  the  injected  material 
was  originally  homogeneous  and  that  segregation  took  place  sub- 
sequently. 

Uses. — The  material  is  roasted  to  drive  off  the  volatile  con- 
stituents and  the  residue  used  as  a  source  of  vanadium  salts  for 
metallurgical  purposes. 

BIBLIOGRAPHY. 

D.  FOSTER  HEWETT,  Transactions  of  the  American  Institute  of  Mining  Engineers, 

February,  1909,  pp.  292-316.     (Vanadium  Deposits  in  Peru.) 
VV.  F.  HILLEBRAND.     The  Vanadium  Sulphide,  Patronite,  and  its  Mineral  Associates. 

From  Minasraga,  Peru. 

Journal  American  Chemical  Society,  XXIX,  July,  1907. 


III.  HALIDES. 

i.  HALITE;  SODIUM  CHLORIDE;  OR  COMMON  SALT. 

Composition. — NaCl,  =  sodium,  60.6  per  cent;  chlorine,  39.4  per 
cent.  The  natural  substance  is  nearly  always  more  or  less  impure, 
as  noted  later.  Hardness,  2.5;  specific  gravity,  2.1  to  2.6  per  cent. 
Colorless  or  white  when  pure,  but  often  yellowish  or  red  or  purplish 
from  the  presence  of  metallic  oxides  and  organic  matter.  Readily 
soluble  in  cold  water,  and  has  a  saline  taste.  Crystallizes  in  the 
isometric  system,  usually  in  cubes,  rarely  with  octahedral  modifi- 
cations. The  faces  of  the  crystals  (particularly  when  prepared 
artificially)  are  often  cavernous  or  hopper-shaped.  Sometimes 
occurs  in  fibrous  forms,  which  it  has  been  suggested  are  pseudo- 
morphous  after  fibrous  gypsum.  Often  found  in  the  form  of 
massive,  crystalline  granular  aggregates  commonly  known  as  rock 
salt. 


44 


THE   NON-METALLIC  MINERALS. 


Sylvite,  the  chloride  of  potassium,  sometimes  occurs  associated 
with  halite,  where  it  has  formed  under  similar  conditions.  From 
halite  it  can  be  distinguished  by  its  crystalline  form,  that  of  a  com- 
bination of  cube  and  octahedron  (see  Fig.  n),  and  more  biting  taste. 
Owing  to  its  ready  solubility  it  is  rarely  found  in  a  state  of  nature. 
Bischofite,  the  chloride  of  magnesium,  is  still  more  soluble  and  prac- 
tically unknown  except  in  crystals  artilically  produced. 

COMPOSITION   OF  SALT  FROM  VARIOUS  LOCALITIES. 


Varieties  of  Salt. 

Chloride  of  Sodium. 

Chloride  of  Calcium. 

<•**'£?  Chloride  of  Magne- 
*  ^  5  to  -1  sium. 

g 

is 

5 

*0 

£ 

oj 
.C 

J2* 

"3 

CO 

Sulphates  of  Mag- 
nesia and  Soda. 

Carbonates  of  Mag- 
nesia and  Lime. 

Alumina  and  Iron. 

Residue. 

Water. 

Authorities. 

Rock  salt. 
Wieliczka,  white  
Hall  in  Tyrol.  .  . 

IOO 

99-43 

94-57 
98.53 
99-32 
99-55 
98.88 
98.33 
98.55 

96.76 
97-21 
99-77 

o.  25 
0.93 

Bischof. 
Do. 
Heine. 
Fournet. 
G.  H.  Cook. 
C.  B.  Hayden. 
Goessman. 
Do. 

G.  H.  Cook. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Falkenan  & 
Reese. 

Do. 
Do. 
Goessman. 
G.  H.  Cook. 
Do. 
Do. 
Do. 
3-oessman. 
E.  S.  Wayne. 
Goessman. 
Do. 
Do. 
G.  H.  Cook. 

o  .  20 
0.89 

Stassfurt  
Ouled  Kebbah  Algeria.  .  .  . 

Cheshire,  England  

Tr 

o  45 

o  .  33 

Petite  Anse,  Louisiana  

Tr. 
0.99 

Tr 

0.79 

0.04 
o  .02 

0.14 
0.26 

O  .  OI 

1.48 
o.44 

1.56 
0.54 
0.08 

O.OI 

0.07 

Cardona,  Spain  

Sea  salt. 
Turks  Island  . 

0.64 
0.24 

0.90 
1-75 
0.14 

St.  Martin's  
St  Kitts 

.... 

Cura§oa  

99-85 
95-76 
94.17 
96.78 
94.91 
98.435 

96.36 
97-39 
97-03 

o  .  03 

0.12 

Cadiz  
Lisbon  
Trapani,  Sicily  

Martha's  Vineyard  
Pacific  coast  (Union  Pacific 
Salt  Company)  

Salt  from  springs  and  lakes. 
Cheshire,  England  
Dienze,  German  Lorraine.  .  . 
Goderich,  Ontario  

0-57 
i  .  ii 
0.49 
0.24 

0.7*5 
0.49 
0.41 
1.42 

0.48 
1-39 
0.68 
o.  19 
o  •  365 

.... 

2.44 
2.84 
1.64 
3-24 

I  .  20 

2.44 

0.50 
i.So 

I  .00 

7.00 

0.  10 

5.10 
3.40 

2.66 
0.80 
4.80 
0.60 
1.28 

O.OI 
O.OI 

0.02 
0.03 

0.18 

1.17 

I  .02 
1-43 
I     26 

0.89 

Kanawha.'West  Virginia.  .  . 

9I-3I 

1.26 

0.43 

o'<58 

O  .  1  1 

Saginaw,  Michigan  
Hocking  Valley,  Ohio  
Pomeroy,  Ohio  
Nebraska  

92.97 
93-07 
96.42 
98.12 
93-o6 
98.28 
97.61 

1  .09 
0.61 
o.53 

0.50 
0.04 
0.18 
0.07 
0.24 

0.33 

0.  10 

0.24 

I  .  I  2 
0.91 
1.03 

O.OI 

0000- 

O  O  H  oo  • 
00>O  OOO  • 

.... 

0.05 

0.16 

0.  12 

Onondaga  "factory  filled". 
Great  Salt  Lake  .  . 

Origin  and  occurrences. — Sodium  in  the  form  of  chloride,  to  which 
is  commonly  given  the  simple  name  of  salt  is  one  of  the  most  widely 
disseminated  of  natural  substances,  and  not  infrequently  occurs  in 


MAUDES.  45 

such  quantities  interstratified  with  other  rocks  as  to  assume  propor- 
tions of  geological  importance.  It  is  to  the  material  occurring  in 
this  form  that  the  name  rock  salt  is  commonly  applied.  As  existing 
to-day  the  principal  deposits  of  the  world  are  a  result  of  evaporation 
of  seawaters  or  deposits  from  springs.  In  either  case  the  ultimate 
source  of  the  material  was  probably  the  same,  the  springs  simply 
deriving  their  supply  from  pre-existing  beds  of  marine  origin.  Inas- 


FIG.  8. — Cluster  of  halite  crystals.     Stassfurt,  Germany. 
[U.  S.  National  Museum.] 

much  as  seawaters  carry  in  solution  other  salts  than  sodium  chloride, 
so  it  happens  that  the  beds  of  marine  salt  are  almost  invariably  con- 
taminated or  interstratified  with  carbonates,  chlorides,  and  sulphates 
of  various  substances  which  have  been  deposited  in  the  inverse  order 
of  their  solubilities  as  evaporation  proceeded.  The  following  list 
includes  the  more  common  associations:  (i)  carbonates  of  lime  and 
magnesia  in  the  form  of  limestones,  marls,  and  dolomites;  (2) 


46  THE  NON-METALLIC  MINERALS. 

sulphate  of  lime  in  the  form  of  anhydrite  and  gypsum;  (3)  chlo- 
ride of  sodium,  or  common  salt,  and  these  followed  in  regular  order 
by  the  sulphates  of  magnesia  and  soda  (Epsom  salt  and  Glauber's 
salt)  and  the  chlorides  of  potassium  and  magnesium.  These  last 
are,  however,  so  readily  deliquescent  that  they  are  rarely  found 
crystallized  out  in  a  state  of  nature,  as  above  noted. 

Such  having  been  the  method  of  formation,  it  is  scarcely  necessary 
to  state  that  salt  beds  are  not  confined  to  strata  of  any  one  geological 
horizon,  but  are  to  be  found  wherever  suitable  circumstances  have 
existed  for  the  formation  and  preservation.  The  beds  of  New 
York  State  and  of  Canada  and  a  part  of  those  of  Michigan  lie  among 
rocks  of  the  Upper  Silurian  Age.  They  are  regarded  by  Professor 
Newberry  as  the  deposits  of  a  great  salt  lake  or  sea  that  formerly  oc- 
cupied central  and  western  New  York,  northern  Pennsylvania,  north- 
eastern Ohio,  and  southern  Ontario,  and  which  he  assumed  to  have 
been  as  large  as  Lake  Huron,  or  possibly  Lake  Superior.  A  part  of  the 
Michigan  beds,  on  the  other  hand,  were  laid  down  near  the  base  of 
the  Carboniferous  series,  as  were  also  those  of  the  Ohio  Valley,  and 
presumably  those  of  Virginia,  while  those  of  Petite  Anse,  Louisiana, 
are  of  Cretaceous,  or  possibly  Tertiary  Age.  The  beds  of  the  West- 
ern States  and  Territories  are  likewise  of  recent  origin,  many  of  them 
being  still  in  process  of  formation. 

The  English  beds  at  Cheshire,  the  source  of  the  so-called  "  Liver- 
pool "  salt,  are  of  Triassic  Age,  as  are  also  those  of  Vic  and  Dieuze 
in  France,  Wurtemburg  in  Germany,  and  Salzburg  in  Austria, 
while  those  of  Wieliczka  in  Austrian  Poland,  and  of  Parajd  in 
Transylvania  are  Tertiary. 

Salt  is  now  manufactured  from  brines  or  mined  as  rock  salt  in 
fifteen  States  of  the  American  Union.  These,  in  the  order  of  their 
apparent  importance,  are  Michigan,  New  York,  Kansas,  California, 
Louisiana,  Illinois,  Utah,  Ohio,  West  Virginia,  Nevada,  Pennsyl- 
vania, Virginia,  Kentucky,  Texas,  and  Wyoming.  At  one  time 
Massachusetts  was  an  important  producer  of  salt  from  sea  waters. 
The  industry  has,  however,  been  gradually  languishing,  and  may 
ere  now  be  wholly  extinct.  In  California  salt  is  obtained  largely 
from  sea  water,  but  also  from  salt  lakes  and  salines.  In  Michigan, 
Ohio,  the  Virginias,  Pennsylvania,  and  Kentucky  salt  is  obtained 


HALIDES..  47 

from  brines  obtained  from  springs  or  by  sinking  wells  into  the  salt- 
bearing  strata,  while  in  New  York,  Kansas,  Louisiana,  and  the 
remaining  States  it  is  obtained  both  from  brines  and  by  mining  as 
rock  salt. 

Of  the  foreign  sources  of  rock  salt  the  following  districts  are  the 
most  important:  (i)  The  Carpathian  Mountains,  (2)  the  Austrian 
and  Bavarian  Alps,  (3)  Western  Germany,  (4)  the  Vosges,  (5)  Jura, 
(6)  Spain,  (7)  the  Pyrenees  and  the  Celtiberian  Mountains,  and 
(8)  Great  Britain,  while  sea  salt  is  an  important  product  of  Turks 
Island  in  the  Bahamas,  of  the  island  of  Sicily,  and  of  Cadiz,  Spain. 

Space  can  here  be  devoted  to  details  concerning  but  a  few  of  these 
localities,  preference  naturally  being  given  to  those  of  the  United  States. 

The  beds  of  New  York  State,  of  Ontario,  northern  Pennsylvania, 
northeastern  Ohio,  and  eastern  Michigan  all  belong  to  the  same 
geologic  group — are  the  product  of  similar  agencies.  They  have 
been  penetrated  in  many  places  by  wells,  and  from  the  results  ob- 
tained one  is  enabled  to  form  some  idea  of  their  extent  and  thickness. 
Below  is  given  a  summary  of  results  obtained  in  boring  a  well  to 
a  depth  of  1,517  feet  at  Goderich,  Canada.  Beginning  at  the  sur- 
face, the  rocks  were  passed  through  in  the  following  order : 

Ft.       In. 

1.  Clay,     gravel,     marls,     limestone,    dolomite,    and     gypsum     variously 

interstratified 997  o 

2.  First  bed  of  rock  salt 30  1 1 

3.  Dolomite  with  marls 32  i 

4.  Second  bed  of  rock  salt 25  4 

5 .  Dolomite 6  10 

6.  Third  bed  of  rock  salt 34  10 

7.  Marl,  dolomite,  and  anhydrite 80  7 

8.  Fourth  bed  of  rock  salt , 15  5 

9.  Dolomite  and  anhydrite 7  o 

10.  Fifth  bed  of  rock  salt 13         6 

11.  Marl  and  anhydrite 135         6 

12.  Sixth  bed  of  rock  salt , .       6         o 

13.  Marl,  dolomite,  and  anhydrite 132         o 

Total  thickness  of  formations  passed  through I>517  feet- 
Total  thickness  of  beds  of  salt 126  feet. 

The  section  shows  that  the  ancient  sea  or  lagoon  underwent 
at  least  six  successive  periods  of  desiccation,  and  especial  attention 
is  called  to  the  remarkable  regularity  of  the  deposits.  On  the 
oldest  sea  bottom  (13)  the  carbonates  and  sulphates  of  lime  and 


48  THE   NON-METALLIC  MINERALS. 

magnesia  were  deposited  first,  being  least  soluble.  Then  followed 
the  salt,  and  this  order  is  repeated  invariably.  The  other  con- 
stituents mentioned  as  occurring  in  the  waters  of  lakes  and  seas 
are  not  sufficiently  abundant  to  show  in  the  section,  or  owing  to 
their  ready  solubility  have  been  in  large  part  removed  since  the 
beds  were  laid  down.  Chemical  tests,  however,  reveal  their  presence 
in  small  but  varying  quantities. 

Although  salt  was  manufactured  from  the  brine  of  springs,  near 
Onondaga  Lake,  in  New  York,  as  early  as  1788,  and  has  been  regu- 
larly manufactured  from  the  brine  of  wells  since  1798,  it  was  not 
until  subsequent  to  the  discovery  of  extensive  beds  of  rock  salt  in  the 
Wyoming  Valley,  while  boring  for  petroleum,  that  the  mining  of 
the  material  in  this  form  became  an  established  industry.  In  June, 
1878,  a  bed  of  rock-salt  70  feet  in  thickness  was  found  in  the  valley 
above  mentioned,  at  a  depth  of  1,270  feet.  Subsequently  other 
borings  in  Wyoming,  Genesee,  and  Livingston  counties  disclosed 
beds  at  varying  depths.  In  1885  the  first  shaft  was  sunk  at  Pifford 
by  the  Retsof  Mining  Company,  the  salt  bed  being  found  at  a  depth 
of  1,018  feet.  Other  shafts  have  since  been  sunk,  the  first  about 
a  mile  west  of  the  Retsof,  the  second  about  2  miles  south  of  Leroy, 
and  the  third  at  Livonia,  in  Livingston  County.  The  salt  when 
taken  from  the  bed  is  of  a  gray  color,  due  to  the  presence  of  clay, 
which  renders  solution  and  recrystallization  necessary  when  de- 
signed for  culinary  purposes.  The  thickness  of  the  beds  and  their 
depth  are  somewhat  variable.  The  following  figures  are  quoted 
from  Dr.  Engelhardt's  report.1  At  Morrisville,  in  Madison  County, 
it  is  12  feet  thick  and  at  a  depth  of  1,259  feet;  at  Tully,  in  Onon- 
daga County,  it  varies  from  25  to  318  feet,  at  depths  of  from  974 
to  1,465  feet.  The  seven  beds  found  at  Ithaca  have  a  total  thickness 
of  248  feet,  the  uppermost  lying  at  a  depth  of  2,244  fee*.  In  the 
Genesee  Valley  the  beds  vary  in  depth  from  750  to  2,100  feet,  and 
in  thickness  from  40  to  93  feet.  In  the  Wyoming  Valley  the  depth 
varies  from  610  to  2,370  feet  below  the  surface,  and  in  thickness 
from  12  to  85  feet.2 

1  The  Mineral  Industry,  its  Statistics  and  Trade  for  1892,  by  R.  P.  Rothwell. 

2  For  a  very  complete  historical  and  geological  account  of  these  salt  beds  and  the 
method  of  manufacture,  see  Bulletin  No.  n,  of  the  "New  York  State  Museum,  1893, 
by  F,  J.  H.  Merrill. 


HALIDES.  49 

Ohio. — The  first  attempts  at  salt  making  in  this  State  was  made 
in  1798  with  brines  from  salt  springs  in  Jackson  County.  These, 
which  became  known  as  the  Scioto  Valley  Works,  were  abandoned 
about  1818  owing  to  the  discovery  of  richer  brines  in  the  Kanawha 
Valley  and  elsewhere.  Drilling  for  salt  began  in  the  Muskingum 
Valley  near  Zanesville  in  1817,  and  by  1833  the  output  of  this  val- 
ley alone  amounted  to  300,000  or  400,000  bushels  annually.  At 
the  present  date  (1909)  the  principal  works  are  in  Meigs,  Morgan, 
Franklin,  Wayne,  Medina,  and  Summit  counties.  During  the  years 
immediately  following  the  Civil  War  there  were  thirteen  furnaces 
in  the  State  for  the  evaporation  of  brines.  The  number  has  gradually 
declined  to  five,  owing  to  the  cheaper  production  from  wells  in 
Michigan  and  New  York.  The  densest  of  the  Ohio  brines  come 
from  the  Berea  Grits,  but  the  amount  is  small;  the  so-called  Big 
Salt  Sand  is  the  most  prolific  source.  The  wells  vary  in  depth 
from  1,000  to  2,000  feet.1 

Michigan. — The  salt-producing  areas  of  this  State  are,  so  far 
as  now  known,  limited  to  the  counties  of  losco,  Bay,  Midland, 
Gratiot,  Saginaw,  Huron,  St.  Clair,  Manistee,  and  Mason,  the  beds 
of  the  Saginaw  Valley  lying  in  the  so-called  Napoleon  sandstone, 
at  the  base  of  the  Carboniferous.  Professor  Winchell  has  estimated 
this  formation  to  cover  an  area  of  some  17,000  square  miles  within 
the  State  limits.  The  beds  of  the  St.  Clair  Valley,  on  the  other 
hand,  are  in  upper  Silurian  strata,  being  presumably  continuous 
with  those  of  Canada.  The  manufacture  of  salt  from  brines  pro- 
cured from  these  beds  began  in  the  Saginaw  Valley  in  1860,  and 
has  since  extended  to  the  other  regions  mentioned.  According  to 
F.  E.  Engelhardt  the  rock-salt  deposits  in  the  Upper  Silurian  beds, 
with  a  thickness  of  115  feet,  were  reached  at  Marine  City,  in  St. 
Clair  County,  at  a  depth  of  1,633  ^eet5  at  St.  Clair,  St.  Clair  County, 
at  a  depth  of  1,635  feet>  and  with  a  thickness  of  35  feet.  At  Caseville, 
in  Huron  County,  the  beds  lie  at  a  depth  of  1,164  feet,  and  at  Bay 
City,  Saginaw  Bay,  at  2,085  feet>  tne  salt  beds  being  115  feet  in 
thickness.  At  Manistee  the  bed  is  34  feet  thick,  lying  2,000  feet 
below  the  surface,  while  at  Muskegon,  in  the  Mason  well,  it  was 
50  feet  thick  at  a  depth  of  2,260  feet. 

1  Bulletin  No.  8,  Geological  Survey  of  Ohio,  1906. 


50  THE  NON-METALLIC  MINERALS. 

Kansas.— In  this  State  the  rock  salt  occurs  in  beds  regarded  as  of 
Permian  age,  and  has  been  reached  by  means  of  shafts  in  several 
counties  in  the  southern  and  central  part  of  the  State.  The  following 
is  a  section  of  a  shaft  sunk  in  Kingman  in  1888-89: 

Feet. 
"Red-beds,"  red  arenaceous,   limestones,   ferruginous  clays,   and  clay  shales 

with  thin  streaks  of  gray  shales  and  bands  of  gypsum  as  satin  spar 450 

Gray  or  bluish  "slate,"  with  2  feet  of  limestone  at  500  feet 140 

Red  clay  shale 4 

Gray  "slate,"  with  occasional  streaks  of  limestone,  2  to  8  inches  thick,  and  some 

salt  partings  and  satin  spar  with  ferruginous  stain 78 

First  rock  salt,  pure  white 2 

Shale  and  "slate,"  bluish,  with  vertical  and  other  seams  of  salt,  from  i  to  3 

inches  thick 26 

Rock  salt 4 

Shales,  with  salt 1 1 

Rock  salt 7 

Shale 3 

Rock  salt 3 

Salt  and  shale,  alternate  thin  seams 62 

Rock  salt ii 

Shale i  iV 

Rock  salt 5 

Shales  and  limestone 8 

Rock  salt,  bottom  of  it  not  reached 5 

Total 820 

Borings  and  shafts  have  also  proven  the  existence  of  beds  of  salt 
in  other  parts  of  the  State,  as  at  Kanopolis,  Lyons,  Caldwell,  Rago, 
Pratt,  and  Wilson.  According  to  Dr.  Robert  Hays1  it  is  safe  to 
assume  that  beds  of  rock  salt  from  50  to  150  feet  in  thickness  under- 
lie fully  half  the  area  from  the  south  line  of  the  State  to  north  of 
the  Smoky  River,  an  area  from  20  to  50  miles  in  width.  Although 
the  mining  of  rock  salt  began  in  this  region  only  in  1888,  the  annual 
output  has  already  reached  over  1,000,000  barrels. 

Louisiana. — Salt  in  this  State  is  derived  from  Petite  Anse,  a 
small  island  rising  from  the  marshes  on  the  southern  coast  and  con- 
nected with  the  mainland  by  a  causeway  some  2  miles  in  length. 
According  to  E.  W.  Hilgard2  the  deposit  is  probably  of  Cretaceous 
Age,  and  presumably  but  a  comparatively  small  residual  mass 

1  Geological  and  Mineral  Resources  of  Kansas,  1893,  p.  44. 

2  Smithsonian  Contributions  to  Knowledge,  XXIII.     On  the  Geology  of  Lower 
Louisiana  and  the  Salt  Deposit  on  Petite  Anse  Island. 


MAUDES. 


of  beds  once  extending  over  a  much  larger  area,  but  now  lost  through 
erosion.  (See  Fig.  10.)  G.  D.  Harris,1  however,  regards  them  as 
deposits  from  springs  ascending  from  deep-seated  sources  along  lines 
of  faults,  the  dome-shaped  structure  being  due  to  the  gradual 


MAP  OF  THE 

TECHE  OR  ATTAKAPAS  COUNTRY, 
LOUISIANA,  U.S. 

Showing  Location  of  the 
AVERY    SALT    MINE 

AND 
PETITE  ANSE  ISLAND 


sSk 


FIG.  9. — Map  of  Petite  Anse,  Louisiana. 
[After  Hilgard.] 

forcing  up  of  the  deposit  first  formed  by  the  crystallization  of  new 
material  brought  up  by  hydrostatic  pressure  from  beneath. 

Kentucky.  —  Salt  in  Kentucky  is  obtained  from  the  brine  of 
springs  and  wells  in  Carboniferous  limestone.  In  Meade  County 
brine  accompanies  the  natural  gas,  the  latter  in  some  cases  being 

1  Economic  Geologist,  IV,  No.  i,  1909. 


THE  NON-METALLIC  MINERALS. 


utilized  as  fuel  for 
its  evaporation. 
Springs  in  Webster 
County  furnished 
salt  for  Indians  long 
anterior  to  the  occu- 
pancy of  the  county 
by  whites,  and  frag- 
ments of  their  clay 
kettles  and  other 
utensils  used  in  the 
work  of  evapora- 
tion are  still  occa- 
sionally found. 

Texas. — The  oc- 
currences of  salt  are 
numerous  and  wide- 
spread. Along  the 
coast  are  many  la- 
goons and  salt  lakes, 
from  which  con- 
siderable quantities- 
are  taken  annually. 
11  Besides  the  lakes 
along  the  shores 
many  others  occur 
through  western 
Texas,  reaching  to 
the  New  Mexico 
line,  while  north  east 
of  these,  in  the  Per- 
mian region,  the 
constant  recurrence 
of  such  names  as 
Salt  Fork,  Salt 
Creek,  etc.,  tell  of 
the  prevalence  of 


MAUDES.  53 

similar  conditions."  In  addition  to  the  brines  there  are  extensive 
beds  of  rock  salt.  That  which  is  at  present  best  developed  is 
located  in  the  vicinity  of  Colorado  City,  in  Mitchell  County.  The 
bed  was  found  at  a  depth  of  850  feet,  with  a  thickness  of  140  feet. 
At  the  "  Grand  Saline"  in  Van  Zandt  County,  a  bed  of  rock  salt 
over  300  feet  in  thickness  was  found  at  a  depth  of  225  feet. 

England.- — In  England  the  salt  occurs  at  Cheshire  in  two  beds 
interstratined  with  marls  and  clays.  The  upper,  with  a  thickness 
varying  from  80  to  90  feet,  lies  at  a  depth  of  some  120  feet  below 
the  surface,  and  the  second  at  a  depth  of  226  feet  has  a  thickness 
varying  between  96  and  117  feet.  The  accompanying  general 
sections  are  from  Davies'  Earthy  and  other  Economic  Minerals.  m _ 


DETAILED    SECTION    OF    STRATA    SUNK    THROUGH    AT    WITTON,    NEAR    NORTHWICH, 
TO   THE   LOWER  BED   OF   SALT. 

Ft.  In. 

1.  Calcareous  marl 15  o 

2.  Indurated  red  clay 4  6 

3.  Indurated  blue  clay  and  marl 7  o 

4.  Argillaceous  marl i  o 

5.  Indurated  blue  clay i  o 

6.  Red  clay  with  sulphate  of  lime  in  irregular  branches 4  o 

7.  Indurated  red  clay  with  grains  of  sulphate  of  lime  interspersed 4  o 

8.  Indurated  brown  clay  with  sulphate  of  lime  crystallized  in  irregular  masses 

and  in  large  proportions 12  o 

9.  Indurated  blue  clay  with  laminae  of  sulphate  of  lime 4  6 

10.  Argillaceous  marl 4  o 

1 1 .  Indurated  brown  clay  laminated  with  sulphate  of  lime 3  o 

12.  Indurated  blue  clay  laminated  with  sulphate  of  lime 3  o 

13.  Indurated  red  and  blue  clay 12  o 

14.  Indurated  brown  clay  with  sand  and  sulphate  of  lime  irregularly  inter- 

spersed through  it.     The  fresh  water,   at  the  rate  of  360  gallons  a 

minute,  forced  its  way  through  this  stratum 13  o 

15.  Argillaceous  marl 5  o 

1 6.  Indurated  blue  clay  with  sand  and  grains  of  sulphate  of  lime 3  9 

17.  Indurated  brown  clay  as  next  above 15  o 

18.  Blue  clay  as  strata  next  above i  6 

19.  Brown  clay  as  strata  next  above 7  o 

20.  The  top  bed  of  rock  salt 75  o 

21.  Layers  of  indurated  clay  with  veins  of  rock  salt  running  through  them 31  6 

22.  Lower  bed  of  rock  salt 115  o 

Total 34I  9 


54  THE  NON-METALLIC  MINERALS. 

Poland. — At  Wieliczka,  in  Austrian  Poland,  the  salt  occurs  in 
massive  beds  stated  to  extend  over  an  area  some  20  by  500  miles,  with 
a  maximum  thickness  of  1,200  feet.  At  Parajd,  in  Transylvania, 
beds  belonging  to  the  same  geological  horizon  are  estimated  to 
contain  upward  of  10,000,000,000,000  cubic  feet  of  salt. 


S 

J 


4b 


FIG.   ii. — Cluster  of  sylvite  crystals,  showing  characteristic  cubo-octahedral  forms. 

Stassfurt,  Germany. 
[U.  S.  National  Museum.] 

Germany. — One  of  the  most  remarkable  deposits  of  the  world, 
remarkable  for  its  extent  as  well  as  for  the  variety  of  its  products,  is 
that  of  Stassfurt,  in  Prussian  Saxony.  On  account  of  its  unique  char- 
acter, as  well  as  its  commercial  importance,  being  to-day  the  chief 
source  of  natural  potash  salts  of  the  world,  a  little  space  may  well  be 
given  here  to  a  detailed  description.1 

1  Journal  of  the  Society  of  Chemical  Industry,  II,  1883,  pp.  146,  147., 


MAUDES.  55 

Stassfurt  is  about  25  miles  southwest  of  the  city  and  fortress  of 
Magdeburg,  in  Prussia.  It  lies  in  a  plain  intersected  by  the  river 
Bode,  which  takes  its  rise  in  the  Harz  Mountains.  The  salt  industry 
here  is  a  very  old  one,  dating  back  as  far  as  the  year  806.  Previous 
to  1839  the  salt  was  produced  from  brine  pumped  from  wells  sunk 
about  200  feet  into  the  rock.  The  brine,  in  the  course  of  time, 
•became  so  weak  that  it  was  impossible  to  carry  on  the  manufacture 
without  loss.  In  1839  the  Prussian  Government  commenced  bor- 
ing with  the  object  of  discovering  the  whereabouts  of  the  bed  of  rock 
salt  from  which  the  brine  had  been  obtained.  In  1843,  seven  years 
after  the  commencement  of  the  borings,  the  top  of  the  rock  salt  was 
reached  at  a  depth  of  256  meters.  The  boring  was  continued  through 
another  325  meters  into  the  rock  salt  without  reaching  the  bottom 
of  the  layer.  At  this  total  depth  of  581  meters  the  boring  was  sus- 
pended. On  analyzing  the  brine  obtained  from  the  bore-hole,  it 
was  found  to  consist,  in  100  parts  by  weight,  of — 

Sulphate  of  calcium 4.01 

Chloride  of  potassium 2.24 

Chloride  of  magnesium T9-43 

Chloride  of  sodium 5.61 

This  result  was  not  only  unexpected,  but  disappointing,  since  the 
presence  of  chloride  of  magnesium  in  such  quantities  dispelled  for 
the  time  all  hopes  of  striking  pure  rock  salt.  The  Government, 
however,  guided  by  the  opinions  expressed  by  Dr.  Karsten  and 
Professor  Marchand,  to  the  effect  that  the  presence  of  chloride  of 
magnesium  in  such  quantities  was  probably  due  to  a  deposit  lying 
above  the  rock  salt,  determined  to  further  investigate  the  matter, 
and  in  the  year  1852  the  first  shaft  was  commenced,  which  after  five 
years  had  penetrated,  at  a  depth  of  330  meters,  into  a  bed  of  rock  salt, 
passing  on  its  way,  at  a  depth  of  256  meters,  a  bed  of  potash  and 
magnesia  salts  of  a  thickness  of  25  meters. 

On  referring  to  the  section  of  the  mines  (Plate  II)  it  will  be  seen 
that  the  lowest  deposit  of  all  consists  of  rock  salt.  The  bore-hole 
was  driven  381  meters  into  it  without  reaching  the  bottom  of  the 
layer.  Its  depth  is  therefore  unknown.  The  black  lines  drawn 


$6  THE    NON-METALLIC  MINERALS. 

through  the  rock-salt  deposit  represent  thin  layers  of  anhydrite 
7  millimeters  thick,  and  almost  equidistant.  The  lines  at  the  top 
of  the  rock  salt  represent  thin  layers  of  Potyhallite,  the  trisulphate 
of  potash,  magnesia,  and  lime.  The  deposit  lying  immediately 
on  the  bed  of  rock  salt  consists  chiefly  of  the  mineral  Kieserite,  a 
sulphate  of  magnesia.  Still  farther  toward  the  surface  the  deposit 
consists  of  the  double  chloride  of  potassium  and  magnesium,  known 
as  Carnallite,  mixed  with  sulphate  of  magnesia  and  rock  salt.  The 
deposit  to  the  right,  on  the  rise  of  the  strata,  consists  of  the  double 
sulphate  of  potash  and  magnesia  combined  with  one  equivalent  of 
chloride  of  magnesium,  and  intermingled  with  common  salt  to  the 
extent  of  40  per  cent.  The  double  sulphate  is  known  as  Kainite 
and  is  a  secondary  formation,  resulting  from  the  action  of  a  limited 
quantity  of  water  on  a  mixture  of  sulphate  of  magnesia  and  the 
double  chloride  of  potassium  and  magnesium,  as  contained  in  the 
uppermost  deposit  previously  spoken  of. 

Sixteen  different  minerals  have  been  discovered  in  the  Stassfurt 
deposits.  They  may  be  divided  into  primary  and  secondary  for- 
mations. Those  of  primary  formation  are  rock  salt,  Anhydrite, 
Polyhallite  (K2SO4,  MgSO4,  2CaSO4,  2H2O)  Kieserite  (MgSO4, 
H2O),  Carnallite  (KCl,MgCl2,  6H2O),  Boracite  (2(Mg3B8O15), 
MgCl2),  and  Douglasite  (2KCl,FeCl2,  2H2O).  Those  of  secondary 
formation,  resulting  from  the  decomposition  of  the  primary  minerals 
are  nine  in  number,  namely:  Kainite  (K2SO4,  MgSO4,  MgCl26H2O) ; 
Sylvite  (KC1);  Tachydrite  (CaCl2,  2  MgCl2  +  i2H2O);  Bischofite 
(MgCl2,  6H2O) ;  Krugite  (K2SO4,  MgSO4,  4CaSO4,  2H2O) ;  Reich- 
ardtite  (MgSO4,  7H2O);  Glauberite  (CaSO4,  Na2SO4);  Schonite 
(K2SO4,  MgSO4,  6H2O),  and  Astrakanite  (MgSO4,  4H2O).  Only 
four  of  these  minerals  have  any  commercial  value,  namely:  Carnallite, 
Kainite,  Kieserite,  and  rock  salt.  The  yield  of  boracite,  which  is 
found  in  nests  in  the  Carnallite  region  of  the  mine,  is  too  insignifi- 
cant to  be  classed  among  those  just  mentioned. 

In  certains  parts  of  the  Carnallite  region,  the  rock  salt  is  found 
crystallized  in  the  form  of  the  cube  and  the  octahedron,  sometimes 
colored  different  shades  of  red  and  blue. 

Methods  of  mining  and  manufacture.-  In  the  manufacture  of 
salt  three  principal  methods  are  employed.  The  first,  if,  indeed,  it 


Prussian  ShaFts. 

\^'ui:fa('e^DTif^^i.^\^2^^--' 

\  ""US'  TT^rr-fr^fcZZ?' \  D^^^^^^1  ^'Sy-s      >'  ' '  -1*2)  V#s 

A-rtwr''x.v,e»  ^  .      -   GJli^^ 

-•       '35%%% 

Wfr 


l^iti  .      V 

"*3    !  ° 

;  '••••^^ 

<;-,•. -x '-S,  o 


S  J^N?^?'r^ft€ 

,v  ,x   ,  ;><l^|^.j  p-^      •  cft4^  J  ' '  /•^Sl^/'l'  -y///  /?!& 
'--:-:^f>       *  tJt1     C^^j^^r      ^t^'-fflsfc' 

-t/     '  /&/&'/*. 


SECTION 

/  Or      THE  .     \ 

SALT  DEPOSITS 

AT 

5TASS£URT 


PLATE    II. 

Section  of  Salt  Beds  at  Stassfurt,  Germany. 
[Trans.  Edinburgh  Geological  Society.     Vol.  V,  1884.] 

[Facing  page  56.] 


MAUDES.  57 

can  be  called  manufacture,  consists  in  mining  the  dry  salt  from  an 
open  quarry,  as  in  the  Rio  Virgen  and  Barcelona  deposits,  or  by 
means  of  subterranean  galleries,  the  methods  employed  at  Petite 
Anse  and  in  Galacia. 

At  Petite  Anse  the  method  of  mining  and  preparation,  as  given 
by  Mr.  R.  A.  Pomeroy,1  is  as  follows: 

Mining  is  done  by  means  of  galleries  on  two  levels.  There  are 
1 6  to  25  feet  of  earth  above  the  salt  deposit.  The  contour  of  the 
latter  conforms  nearly  with  that  of  the  surface.  The  working  shaft 
is  168  feet  deep.  The  depth  of  the  first  level  of  floor  is  90  feet;  to 
the  second,  70  feet  farther.  The  remaining  8  feet  are  used  for  a 
dump.  The  galleries  of  the  first  level  were  run,  on  an  average,  40 
feet  in  width  and  25  feet  and  upwards  in  height,  leaving  supporting 
pillars  40  feet  in  diameter. 

The  galleries  of  the  second  level  are  run  80  feet  in  width  and 
45  feet  in  height,  leaving  supporting  pillars  60  feet  in  diameter. 
The  lower  pillars  are  so  left  that  the  weight  of  the  upper  ones  rests 
upon  them  in  part,  if  not  wholly,  with  a  thickness  of  at  least  25  feet 
of  salt  rock  between.  Galleries  aggregating  nearly  i  mile  in  length 
have  been  run  on  the  upper  level  and  some  700  feet  on  the 
lower. 

The  salt  as  it  comes  from  the  mine  is  dumped  into  corrugated 
cast-iron  rolls,  which  crush  it.  Next  it  goes  into  revolving  screens, 
which  take  out  the  coarser  lumps  for  " crushed  salt"  and  let  the 
fine  stuff  pass  to  the  buhrstones.  These  grind  the  salt,  and  from 
them  it  goes  to  the  pneumatic  separators,  which  take  out  the  dust 
and  separate  the  market  salt  into  various  grades.  Taking  the  dust 
out  is  essential  to  the  production  of  a  salt  that  will  not  harden,  since 
the  fine  particles  of  dust  deliquesce  readily,  and  on  drying  cement 
the  coarse  particles  together. 

On  the  Colorado  Desert  the  salt  occurs  in  the  form  of  a  crust  a 
foot  or  more  in  thickness,  resting  on  a  shallow  lake  of  brine.  This 
crust,  which  is  covered  with  a  thin  layer  of  dust  and  sand  blown 
over  it  from  the  surrounding  desert,  is  cut  away  longitudinally,  much 

1  Transactions  of  the  American  Institute  Mining  Engineers,  XVII,  1888,  1889, 
p.  in. 


58  THE  NON-METALLIC  MINERALS. 

as  ice  is  cut  in  the  North.  When  loosened,  the  block,  falling  into 
the  water  beneath,  is  cleaned  of  its  impurities,  and  is  then  thrown 
out  on  a  platform  to  dry,  after  which  it  is  ground  and  packed  for 
market.  In  many  parts  of  the  arid  West  the  salt  is  obtained  merely 
by  shoveling  up  the  impure  material  deposited  by  the  evaporation 
of  salt  lakes  and  marshes  during  seasons  of  drought.  In  this  way 
is  obtained  a  large  share  of  the  material  used  in  chloridizing  ores. 

In  the  preparation  of  salt  from  sea  water,  solar  evaporation  alone 
is  relied  upon  nearly  altogether.  This  method,  like  the  next  to  be 
mentioned,  depends  for  its  efficiency  upon  the  fact  already  noted 
— that  sea  water  holds  in  solution  besides  salt  various  other  ingre- 
dients, which,  owing  to  their  varying  degrees  of  solubility,  are  depos- 
ited at  different  stages  of  the  concentration.  In  Barnstable  County, 
Massachusetts,  it  was  as  follows:  A  series  of  wooden  vats  or  tanks, 
with  nearly  vertical  sides  and  about  a  foot  in  depth,  is  made  from 
planks.  These  are  set  upon  posts  at  different  levels  above  the 
ground,  and  so  arranged  that  the  brine  can  be  drawn  from  one 
to  another  by  means  of  pipes,.  Into  the  first  and  highest  of  these 
tanks,  known  as  the  "long  water  room,"  the  water  was  pumped  di- 
rectly from  the  bay  or  artificial  pond  by  means  of  windmills,  and  there 
allowed  to  stand  for  a  period  of  about  ten  days,  or  until  all  the  sed- 
iment it  may  carry  was  deposited.  Thence  it  was  run  through  pipes 
to  the  second  tank,  or  "  short  water  room,"  where  it  remained  exposed 
to  evaporation  for  two  or  three  days  longer,  when  it  was  drawn  off 
into  the  third  vat,  or  "pickle  room,"  where  it  stood  until  concen- 
tration had  gone  so  far  that  the  lime  was  deposited  and  a  thin  pellicle 
of  salt  began  to  form  on  the  surface.  It  was  then  run  into  the  fourth 
and  last  vat,  where  the  final  evaporation  took  place  and  the  salt  itself 
crystallized  out.  Care  was  requisite,  however,  lest  the  evapora- 
tion proceed  too  far,  in  which  case  sulphate  of  soda  (Glauber's  salt) 
and  other  injurious  substances  could  also  be  deposited,  and  the  quality 
of  the  sodium  chloride  thereby  be  greatly  deteriorated. 

As  to  the  capabilities  of  works  constructed  as  above,  it  may  be 
said  that  during  a  dry  season  vats  covering  an  area  of  3,000  square 
feet  would  evaporate  about  32,500  gallons  of  water,  thus  producing 
some  100  bushels  of  salt  and  400  pounds  of  Glauber's  salt.  The 
moist  climate  of  the  Atlantic  States,  however,  necessitates  the  roof- 


HALIDES.  59 

ing  of  the  vats  in  such  a  manner  that  they  can  be  protected  or  exposed 
as  desired,  thereby  greatly  increasing  the  cost  of  the  plant.  Sundry 
parts  of  the  Pacific  coast,  on  the  other  hand,  owing  to  their  almost 
entire  freedom  from  rains  during  a  large  part  of  the  year,  are  pecu- 
liarly adapted  for  the  manufacture  by  solar  evaporation.  Hence, 
while  the  works  on  the  Atlantic  coast  have  nearly  all  been  discon- 
tinued, there  has  been  a  corresponding  growth  in  the  West,  and 
particularly  in  the  region  about  San  Francisco  Bay. 

The  methods  of  procedure  in  the  California  works  do  not  differ 
materially  from  that  already  given,  excepting  that  no  roofs  are 
required  over  the  vats,  which  are  therefore  made  much  larger.  One 
of  the  principal  establishments  in  Alameda  County  may  be  described 
as  follows :  The  works  are  situated  upon  a  low  marsh,  naturally  cov- 
ered by  high  tides.  This  has  been  divided,  by  means  of  piles  driven 
into  the  mud  and  by  earth  embankments,  into  a  series  of  seven  vats 
or  reservoirs,  all  but  the  last  of  which  are  upon  the  natural  surface 
of  the  ground — that  is,  without  wooden  or  other  artificial  bottoms. 
The  entire  area  inclosed  in  the  seven  vats  is  about  600  acres,  neces- 
sitating some  15  miles  of  levees.  The  season  of  manufacture  lasts 
from  May  to  October.  At  the  beginning  of  the  spring  tides,  which 
rise  some  12  to  15  inches  above  the  marsh  level,  the  fifteen  gates  of 
reservoir  No.  i,  comprising  some  300  acres,  are  opened  and  the 
waters  of  the  bay  allowed  to  flow  in.  In  this  great  artificial  salt  lake 
the  water  is  allowed  to  stand  until  all  the  mud  and  filth  have  become 
precipitated,  which  usually  requires  some  two  weeks.  Then,  by 
means  of  pumps  driven  by  windmills,  the  water  is  driven  from 
reservoir  to  reservoir  as  concentration  continues,  till  finally  the  salt 
crystallizes  out  in  No.  7,  and  the  bittern  is  pumped  back  into  the 
bay.  The  annual  product  of  the  works  above  described  is  about 
2,000  tons. 

A  somewhat  similar  process  is  pursued  in  the  manufacture  of  salt 
from  inland  lakes,  as  the  Great  Salt  Lake,  Utah. 

The  water  is  pumped  from  the  lake  into  ponds  prepared  for 
its  reception  and  situated  above  the  level  of  the  lake  surface. 
In  the  first  pond  the  mechanically  suspended  matters  are  left  as 
sediment  or  scum,  and  the  water  passes  into  the  second  in  a  clear 
condition.  The  ponds  cover  upward  of  a  thousand  acres,  and  the 


60  THE  NON-METALLIC  MINERALS. 

dra'n  channels  leading  from  them  aggregate  9  miles  in  length. 
The  pumping  continues  through  May,  June,  and  July.  A  fair  idea 
of  th3  rate  of  evaporation  in  the  thirsty  atmosphere  of  the  Great  Basin 
may  be  gained  from  contemplating  the  fact  that  to  supply  the  volume 
of  water  disappearing  from  the  ponds  by  evaporation  requires  the 
action  of  the  pumps  10  hours  daily  in  June  and  July.  This  is  equal 
to  the  carrying  away  of  8,400,000  gallons  per  day  from  the  surface 
of  the  ponds. 

"The  'salt  harvest'  begins  in  August,  soon  after  the  cessation 
of  pumping,  and  continues  till  all  is  gathered,  frequently  extending 
into  the  spring  months  of  the  succeeding  year.  An  average  season 
yields  a  layer  of  salt  7  inches  deep,  which  amount  would  be  deposited 
from  49  inches  of  lake  water.  The  density  at  which  salt  begins  to 
deposit,  as  observed  at  the  ponds  and  confirmed  by  laboratory 
experiments,  is  1.2121,  and  that  of  the  escaping  mother  liquors  is 
1.2345.  The  yield  of  salt  is  at  the  rate  of  150  tons  per  inch  per 
acre.1 

Owing  to  the  depth  below  the  surface  of  the  salt  beds  in  Ohio, 
Michigan,  and  other  inland  States,  the  material  is  never  mined  as 
in  the  cases  first  mentioned,  but  is  pumped  to  the  surface  as  a  brine 
and  there  evaporated  by  artificial  heat.  In  the  Warsaw  Valley  region 
the  beds  lie  from  800  to  2,500  feet  below  the  surface,  and  are  reached 
by  wells.  These  are  bored  from  5^  to  8  inches  in  diameter  and  are 
cased  with  iron  pipes  down  to  the  salt.  Inside  the  first  pipe  is  then 
introduced  a  second  2  inches  in  diameter,  with  perforations  for  a 
few  feet  at  its  lower  end,  and  which  extends  nearly,  if  not  quite,  to 
the  bottom.  Fresh  water  is  then  allowed  to  run  from  the  surface 
down  between  the  two  pipes.  This  dissolves  the  salt,  and  forms  a 
strong  brine  which,  being  heavier,  sinks  to  the  bottom  of  the  well 
and  is  pumped  up  through  the  smaller  or  inner  tube.  At  Syracuse 
the  wells  are  not  sunk  into  the  salt  bed  itself,  but  into  an  ancient 
gravel  deposit  which  is  saturated  with  the  brine.  Here  the  intro- 
duction of  water  from  the  surface  is  done  away  with.  Iri  those 
cases,  not  at  all  uncommon,  where  the  brine  flows  naturally  to  the 
surface  in  the  form  of  a  spring,  pumping  is  of  course  dispensed  with. 

1  J.  E.  Talmage,  Science,  XIV,  1889,  p.  445. 


HALIDES.  61 

The  methods  of  evaporation  vary  somewhat  in  detail.  In  New 
York  the  brine  is  run  in  a  continuous  stream  in  large  pans  some  130 
feet  long  by  20  feet  wide  and  18  inches  deep.  As  it  evaporates  the 
salt  is  deposited  on  the  bottom,  and,  by  means  of  long-handled 
scrapers,  is  drawn  on  the  sloping  sides  of  the  pan.  Here  it  is  allowed 
to  drain,  and  is  afterwards  taken  to  the  storage  bins  for  packing  or 
grinding.1  Salt  thus  produced,  it  should  be  noticed,  is  never  so 
coarse  as  the  so-called  rock  salt,  or  that  which  has  formed  by  natural 
evaporation.  In  Michigan  the  brine  from  the  wells  is  first  stored 
in  cisterns,  whence  it  is  drawn  off  into  large  shallow  pans,  known 
technically  as  "  settlers,"  where  it  is  heated  by  means  of  steam  pipes 
to  a  temperature  of  175°,  until  the  point  of  saturation  is  reached. 
It  is  then  drawn  into  a  second  series  of  pans,  called  "grainers," 
where  it  is  heated  to  a  temperature  of  185°,  until  crystallization 
takes  place. 

The  strength  of  brines,  and  therefore  the  quantity  of  water  that 
must  be  evaporated  to  produce  a  given  quantity  of  salt,  varies 
greatly  in  different  localities.  At  Syracuse  the  brine  contains  15.35 
per  cent  of  salt;  at  the  Saginaw  Valley,  17.91  per  cent;  at  Saltville, 
Virginia,  25.97  Per  cent5  while  Salt  Lake  contains  n.86  per  cent, 
and  the  waters  of  San  Francisco  Bay  but  2.37  per  cent.  The  amount 
of  impurities  in  the  final  product  depends  on  the  care  exercised  in 
process  of  manufacture,  rapid  boiling  giving  less  satisfactory  results 
than  slower  methods.  The  Syracuse  salt  has  been  found  to  contain 
98.52  per  cent  sodium  chloride;  California  Bay  salt  98.43  per  cent 
and  99.44  per  cent;  and  Petite  Anse  99.88  per  cent.  The  impurities 
in  these  cases  are  nearly  altogether  chlorides  and  sulphates  of  lime 
and  magnesia. 

In  many  works,  and  particularly  those  of  Michigan  and  Ohio, 
bromine  is  distilled  and  condensed  from  the  bittern  left  from  the 
crystallization  of  the  salt.  It  is  stated  2  that  in  some  of  the  Ohio 
works  the  liquid  remaining  from  the  distillation  of  the  bromine  is 
run  into  a  cistern  and  treated  with  lime.  This  neutralizes  any  acid 

1  For  details,  see  Salt  and  Gypsum  Industries  of  New  York,  by  Dr.  F.  J.  H.  Mer- 
rill, Bulletin  No.  n.  New  York  State  Museum,  1893. 

2  Bulletin  No.  8,  Geological  Survey  of  Ohio,  1906. 


62  THE  NON-METALLIC  MINERALS. 

remaining  from  the  bromine  process.  The  liquid  is  then  con- 
densed by  boiling  in  open  pans,  until  calcium  chloride  separates 
out. 

The  Cheshire  (England)  salt  beds  are  worked  both  by  mining 
as  rock  salt  and  by  pumping  the  brine.  Formerly  both  upper  and 
lower  beds  were  mined,  but  flooding  and  falling  in  of  the  roofs 
caused  the  work  to  be  discontinued  on  the  upper  beds.  That  now 
mined  as  rock  salt  comes  wholly  from  the  lower  bed,  and  being 
impure  is  used  mainly  for  agricultural  purposes. 

At  Wieliczka  the  salt  is  likewise  mined  from  galleries  resembling 
in  a  general  way  those  of  a  coal  mine.  These,  according  to  Brehm,1 
begin  at  a  depth  of  about  95  meters,  forming  several  levels  connected 
by  stairways,  the  lowermost  gallery  being  at  a  depth  of  312  meters, 
or  some  50  meters  below  sea  level.  These  galleries  have  a  total 
length  of  some  680  kilometers.  They  are  connected  with  one 
another  by  means  of  eleven  pits  of  which  seven  are  utilized  for 
hoisting  purposes.  The  work  goes  on  continually  night  and  day 
the  year  through.  The  salt  is  cut  out  in  the  form  of  blocks,  leaving 
huge  chambers,  the  roof  being  sustained  by  means  of  large  columns 
of  salt  left  standing.  The  temperatufe  within  these  chambers  is 
very  uniform,  varying  only  between  10°  and  15°  C.  The  air  is  dry 
and  healthful.  The  miners  hew  out  of  the  salt  statues  of  the  saints, 
pyramids,  and  chandeliers.  One  chamber,  called  the  Chapel  of 
St.  Antoine,  with  its  altar,  statues,  columns,  etc.,  is  still  in  a  condi- 
tion of  perfect  preservation  after  a  lapse  of  two  centuries. 

The  output  of  salt  in  the  United  States  for  1900  amounted  to 
upwards  of  20,000,000  barrels  of  280  pounds  each,  of  which  85  per 
cent  was  from  mines  and  wells  in  New  York,  Michigan,  and  Kansas. 
For  1907  the  output  was  29,704,128  barrels,  valued  at  $7,439,537. 
The  annual  output  for  the  entire  world  amounts  to  upwards  of 
10,000,000  metric  tons. 

Uses. — The  principal  uses  of  salt  have  always  been  for  culinary 
and  preservative  purposes.  Aside  from  these,  it  is  also  used  in 
certain  metallurgical  processes  and  in  chemical  manufacture,  as  in 
the  preparation  of  the  so-called  soda  ash  (sodium  carbonate),  used 

1  Marveilles  de  la  Nature.     La  Terre,  etc.,  p.  315. 


HALIDZS.  63 

in  glass  making,  soap  making,  bleaching,  etc.,  and  in  the  preparation 
of  sodium  salts  in  general.  Clear,  transparent  salt  has  been  utilized 
in  a  few  instances  in  optical  and  other  research  work. 

2.  ELUORITE. 

This  is  a  calcium  fluoride,  CaF2,  =  fluorine,  48.9  per  cent ;  calcium, 
51.1  per  cent.  The  most  striking  features  of  the  mineral  are  its 
cubic  crystallization,  octahedral  cleavage,  and  fine  green,  yellow, 
purple,  violet,  and  sky-blue  colors.  White  and  red-brown  varieties 
are  also  known.  The  mineral  is  translucent  to  transparent,  and 
of  a  hardness  somewhat  greater  than  calcite  (4  of  Dana's  scale). 

Occurrence. — The  mineral  occurs,  as  a  rule,  in  veins,  in  gneiss, 
the  schists,  limestones,  and  sandstones.  It  is  also  a  common  gangue 
of  metallic  ores,  particularly  those  of  lead  and  tin. 

The  principal  American  sources  are  Rosiclare,  in  southern  Illi- 
nois, and  on  the  opposite  side  of  the  Ohio  River,  in  Kentucky,  though 
deposits  have  been  reported  in  Smith,  Trousdale,  and  Wilson  coun- 
ties in  Tennessee,  and  near  Yuma,  Arizona. 

At  Rosiclare  the  fluorspar  occurs  in  what  are  regarded  as  true 
fissure  veins  varying  from  4  to  40  or  more  feet  in  width  in  the 
Lower  Carboniferous  limestone.  The  original  veins  were,  however, 
much  smaller,  the  crevices  having  been  enlarged  by  circulating 
waters,  and  the  present  great  width  being  due  to  a  partial  replace- 
ment of  the  limestone. 

On  the  hanging-wall  side  of  the  veins  the  fluorspar  contents  are 
not  pure,  and  often  contain  fragments  of  the  country  rock.  There 
is  also  no  sharp  contact  of  the  vein  with  the  wall.  Near  the  foot- 
wall  the  fluorspar  is  often  found  in  solid  masses  from  2  to  12  feet 
in  thickness.  With  the  fluorspar  there  is  nearly  always  associated 
calcspar,  galena,  and  sphalerite,  and  occasionally  pyrite,  chalcopy- 
rite,  and  barite. 

The  depth  to  which  the  deposits  extend  has  not  been  determined, 
but  they  have  been  worked  to  a  depth  of  200  feet  without  any  appar- 
ent diminution  in  width  of  the  vein,  and  Emmons  regards  it  as 
reasonable  to  assume  that  they  will  extend  as  far  down  as  the  Trenton 
and  Cambrian  limestone. 

At  the  Riley  mine,  in  Crittenden  County,  Kentucky,  the  fluorite 


64 


THE  NON-METALLIC  MINERALS. 


occurs  as  a  vein  filling  a  fault  fissure  between  the  St.  Louis  (sub- 
Carboniferous)  limestone  on  the  southeast,  and  the  Birdsville  quartz- 
ite  on  the  northwest.  The  vein  is  some  3  to  4^  feet  in  width, 

striking  N.  44°  E.  The  south- 
eastern wall,  so  far  as  exposed, 
consists  of  red  residual  clay  and 
chert,  with  scattered  blocks  of  the 
limestone.  Toward  the  bottom 
of  the  shaft — some  75  feet,  as 
shown  in  Fig.  12 — is  a  strip  of 
shale  about  3  feet  in  thickness, 
apparently  dragged  in  along  the 
fault  plane.  The  vein  filling  mat- 
ter is  mainly  fluorite,  with  some 
white  calcite  and  barite.  Banding, 
parallel  with  the  walls,  is  sometimes 
apparent.  The  fluorite  of  both 
Illinois  and  Kentucky  is  regarded 
as  deposited  from  solutions,  the 
material  being  originally  a  minor 
constituent  of  the  deeper-lying 
limestone,  whence  it  was  leached 
by  ascending  thermal  waters,  the 
activity  of  which  was  excited  by 
the  intrusions  of  the  neighboring 
peridotites. 

In  both  States  the  deposits  are 
worked    by    means    of    shafts  and 


vBand  of  mud,  shale,  quartzite 
and  flouritc 

SCALE 


FIG.  12.— Section  of  fluorite   vein,    drifts.      As  taken  from  the  mine, 

Chittenden  County,  Kentucky  &        mm^l     IS,    in      Some      cases, 

[After  W.  S.  I.  Smith,  Prof.  Paper  U. 

S.  Geological  Survey,  No.  36.]          concentrated    by    a     handcobbing 

machine  and  by  the  use  of  water- 
jigs,  though  in  some  cases  it  is  shipped  directly  from  the  mine 
after  having  been  simply  washed.  In  a  number  of  cases  the 
lead  and  zinc  ores  commingled  with  the  fluorite  are  saved  as  by- 
products. 


MAUDES.  65 

Illinois  and  Kentucky  are  the  principal  sources  of  fluorspar  as 
at  present  mined  in  America.  The  actual  amount  there  existing 
is  probably  more  than  sufficient  to  supply  the  demand  for  many 
years  to  come.  The  average  output  at  date  of  writing  is  between 
40,000  and  50,000  tons,  valued  at  from  $5  to  $10  per  ton,  according 
to  quality. 

Uses. — The  material  is  used  mainly  as  a  flux  for  iron,  in  the 
manufacture  of  opalescent  glass,  and  for  the  production  of  hydro- 
fluoric acid. 

BIBLIOGRAPHY. 

S.  F.  EMMONS.     Fluorspar  Deposits  of  Southern  Illinois. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXI,  1893,  pp. 

3J-53- 
H.  F.  BAIN.     Fluorspar  Deposits  of  Southern  Illinois. 

U.  S.  Geological  Survey,  Bulletin  No.  255,  1905. 
W.  S.  I.  SMITH.     Lead,  Zinc,  and  Fluorspar  Deposits  of  Western  Kentucky. 

U.  S.  Geological  Survey,  Prof.  Paper  No.  36,  1905,  pp.  107-207. 


3.    CRYOLITE. 

Composition. — Na3AlF6,  =  aluminum,  12.8  per  cent;  sodium,  32.8 
per  cent;  fluorine,  54.4  per  cent.  The  mineral  is,  as  a  rule,  of  snow- 
white  color,  though  sometimes  reddish  or  brownish,  rarely  black, 
and  coarsely  crystalline  granular,  translucent  to  subtransparent.  It 
has  a  hardness  of  2.5 ;  specific  gravity  of  2.9  to  3,  and  in  thin  splinters 
may  be  melted  in  the  flame  of  a  candle. 

The  name  is  from  the  Greek  word  xpvos,  ice,  in  allusion  to 
its  translucency  and  ice-like  appearance. 

Mode  oj  occurrence. — Cryolite  occurs,  as  a  secondary  product, 
in  the  form  of  veins.  It  is  rarely  found  in  sufficient  abundance  to 
be  of  commercial  value,  the  supply  at  present  coming  almost  wholly 
from  Evigtok  in  South  Greenland.  The  country  rock  here  is  said 
to  be  granite,  and  the  vein  as  described  in  1866  l  was  150  feet  in 

1  Paul  Quale,  Report  of  Smithsonian  Institution,  1866,  p.  398, 


66  THE  NON-METALLIC  MINERALS. 

greatest  breadth,  and  was  exposed  for  a  distance  of  600  feet.  The 
principal  mineral  of  the  vein  was  cryolite,  but  quartz,  siderite,  galena, 
and  chalcopyrite  were  constant  accompaniments,  irregularly  dis- 
tributed through  the  mass.  In  1890  the  mine  as  worked  was  de- 
scribed as  elliptical  in  shape,  450  feet  long  by  150  feet  wide,  the  pit 
being  some  100  feet  deep.  The  drills  had  penetrated  150  feet  deeper 
and  found  cryolite  all  the  way.  Johnstrup,  as  quoted  by  Dana,1 
describes  the  cryolite  as  " limited  to  the  granite;  he  distinguishes  a 
central  and  a  peripheral  part;  the  former  has  an  extent  of  500  feet 
in  length  and  1,000  feet  in  breadth,  and  consists  of  cryolite  chiefly, 
with  quartz,  siderite,  galena,  sphalerite,  pyrite,  chalcopyrite,  and 
wolframite  irregularly  scattered  through  it.  The  peripheral  por- 
tion forms  a  zone  about  the  central  mass  of  cryolite;  the  chief  min- 
erals are  quartz,  feldspar,  and  ivigtite,  also  fluorite,  cassiterite, 
molybdenite,  arsenopyrite,  columbite.  Its  inner  limit  is  rather 
sharply  defined,  though  there  intervenes  a  breccia-like  portion  con- 
sisting of  the  minerals  of  the  outer  zone  inclosed  in  cryolite;  be- 
yond this  it  passes  into  the  surrounding  granite  without  distinct 
boundary." 

Cryolite  in  limited  quantity  occurs  at  the  southern  base  of  Pike's 
Peak,  in  Colorado,  and  north  and  west  of  St.  Peter's  Dome.  It  is 
found  in  vein-like  masses  of  quartz  and  microcline  embedded  in 
granite. 

Uses. — The  material  has  been  utilized  in  the  manufacture  of 
soda,  and  sodium  and  aluminum  salts,  and  to  a  small  extent  in  the 
manufacture  of  glass  and  procelain  ware.  It  is  also  used  in  the 
electrolytic  processes  of  extracting  aluminum  from  its  ores,  as  now 
practiced. 

The  principal  works  utilizing  the  Greenland  cryolite  in  chemical 
manufacture  are,  at  time  of  writing,  those  of  the  Pennsylvania  Salt 
Manufacturing  Company  at  Natrona,  Pennsylvania.  From  5,000 
to  10,000  tons  are  imported  annually,  valued  at  about  $12 
per  ton. 

1  System  of  Mineralogy,  1892,  p.  167. 


OXIDES.  67 


iv.   OXIDES. 

I.    SILICA. 

Quartz. — The  mineral  quartz,  easily  recognized  by  its  insolu- 
bility in  acids,  glassy  appearance,  lack  of  cleavage,  and  hardness, 
which  is  such  that  it  readily  scratches  glass,  is  one  of  the  most  common 
and  widely  disseminated  of  minerals.  Chemically  it  is  pure  silica, 
of  the  formula  SiO2.  It  crystallizes  in  the  hexagonal  system  with 
pyramidal  terminations,  and  is  one  of  the  most  attractive  of  minerals 
for  the  amateur  collector.  The  common  form  is,  however,  massive, 
occurring  in  veins  in  the  older  crystalline  rocks.  Common  sand 
is  usually  composed  mainly  of  quartzose  grains  which,  owing  to 
their  hardness  and  resistance  to  atmospheric  chemical  agencies, 
have  withstood  disintegration  to  the  very  last. 

The  terms  rose,  milky,  and  smoky  are  applied  to  quartzes  which 
differ  from  the  ordinary  type  only  in  tint,  as  indicated.  Chalcedony  is 
the  name  given  to  a  somewhat  horn-like,  translucent  or  transparent 
form  of  silica  occurring  only  as  a  secondary  constituent  in  veins,  or 
isolated  concretionary  masses,  and  in  cavities  in  other  rocks.  Agate 
is  a  banded  variety  of  chalcedony.  The  true  onyx  is  similar  to 
agate,  except  that  the  bands  or  layers  of  different  colors  lie  in  even 
planes.  Jasper  is  a  ferruginous,  opaque  chalcedony,  sometimes  used 
for  ornamental  purposes.  Opal  is  an  amorphous  form  of  silica, 
containing  somewhat  variable  amounts  of  water. 

Quartz  occurs  as  an  essential  constituent  of  granite,  gneiss, 
mica  schist,  quartz  porphyry,  and  liparite,  and  also  as  a  secondary 
constituent  in  the  form  of  veins,  filling  joints  and  cavities  in  rocks  of 
all  kinds  and  all  ages. 

Uses. — The  finer  clear  grades  of  quartz  were  formerly  used  to 
some  extent  for  spectacle  lenses  and  optical  work.  Its  main  value 
is  for  abrading  purposes,  either  as  quartz  sand  or  as  sandpaper, 
and  in  the  manufacture  of  pottery.  For  abrading  purposes  it  is 
crushed  and  bolted,  like  emery  and  corundum,  and  brings  a  price 
barely  sufficient  to  cover  cost  of  handling  and  transportation.  There 
is  a  remarkable  variation  in  quartz  as  relates  to  its  suitability  for 
abrasive  purposes,  some  varieties  on  crushing  giving  rise  to  sharp, 
splintery  fragments  possessing  a  high  degree  of  cutting  or  abrading 


68  THE  NON-METALLIC  MINERALS. 

power,  while  others  yield  sands  that  are  dull  and  of  less  value.     As 

a  rule  the  clear,  glassy  quartz  will  yield  a  sharper  sand  than  the 

opaque  and  milky  forms. 

Ground  quartz  is  used  to  some  extent  as  a  " filler"  in  paints,  and 

as  a  scouring  material  in  soaps.     (See  further  under  Sand  for  glass 

making,  p.  419). 

Flint  is  a  chalcedonic  variety  of  silica  found  in  irregular  nodular 
forms  in  beds  of  Cretaceous  chalk.  These  nodules  break  with  a 
conchoidal  fracture  and  interiorly  are  brownish  to  black  in  color. 
By  the  aboriginal  races  the  flints  were  utilized  for  the  manufacture  of 
knives  and  general  cutting  implements.  Later  they  were  used  in  the 
manufacture  of  gun-flints  and  the  " flint  and  steel"  for  producing 
fire.  At  present  they  are  used  to  some  extent  in  the  manufacture  of 
porcelain,  being  calcined  and  ground  to  mix  with  the  clay  and  give 
body  to  the  ware.  In  this  country  the  same  purpose  is  accomplished 
by  the  use  of  quartz.  Small  round  nodules  of  flint  from  Dieppe, 
France,  are  said  to  be  used  in  the  Trenton  (New  Jersey)  pottery 
works  for  grinding  clay  by  being  placed  in  revolving  vats  of  water 
and  kaolin.  All  the  flint  now  used  in  this  country  is  imported  either 
as  ballast  or  as  an  accidental  constituent  of  chalk. 

As  the  material  is  worth  but  from  $i  to  $2  a  ton  delivered  at 
Trenton,  it  may  be  readily  understood  that  transportation  is  a  rather 
serious  item  to  be  considered  in  developing  home  resources. 

According  to  Mr.  R.  T.  Hill,  nodules  of  black  flint  occur  in  enor- 
mous quantities  in  the  chalky  limestones — the  Caprina  limestones — 
of  Texas.  Numerous  localities  are  mentioned,  the  most  accessible 
being  near  Austin,  on  the  banks  of  the  Colorado  River. 

Buhrstone,  or  burrstone,  is  the  name  given  to  a  variety  of 
chalcedonic  silica,  quite  cavernous,  and  of  a  white  to  gray  or  slightly 
yellowish  color.  The  cavernous  structure  is  frequently  due  to  the 
dissolving  out  of  calcareous  fossils.  The  rock  is  of  chemical  origin 
— that  is,  results  from  the  precipitation  of  silica  from  solution,  and 
presumably  through  the  action  of  organic  matter.  In  France  the 
material  occurs  alternating  with  other  unaltered  Tertiary  strata  in 
the  Paris  basin.  It  is  also  reported  in  Eocene  strata  in  South 
America,  and  in  Burke  and  Screven  counties  along  the  Savannah 
River  in  eastern  Georgia  in  the  United  States.  The  toughness 
of  the  rock,  together  with  the  numerous  cavities,  imparts  a  sharp 


OXIDES.  69 

cutting  power  such  as  renders  it  admirably  adapted  for  millstones, 
and  in  years  past  material  for  this  purpose  has  been  sent  out  from 
French  sources  all  over  the  civilized  world. 

Tripoli  is  the  commercial  name  given  to  a  peculiar  porous  rock 
associated  with  the  Lower  Carboniferous  limestones  of  southwest 
Missouri,  and  regarded  as  having  originated  through  the  leaching 
out  of  the  lime  carbonate  from  a  highly  siliceous  member  of  the 
series.1  The  rock  is  of  a  cream-white  or  slight  pink  cast,  fine  grained 
and  homogeneous,  with  a  distinct  gritty  feel,  and,  though  soft,  suf- 
ficiently tenacious  to  permit  of  its  being  used  in  the  form  of  thin 
disks  of  considerable  size  for  filtering  purposes.  According  to  Hovey  2 
the  deposit  is  known  to  underlie  between  80  and  100  acres  of  land, 
in  the  form  of  a  rude  ellipse,  with  its  longer  diameter  approximately 
north  and  south.  From  numerous  prospect  holes  and  borings  it 
has  been  shown  to  have  an  average  thickness  of  15  feet,  the  main 
quarry  of  the  present  company  showing  a  thickness  of  8  feet.  The 
following  section  is  given  from  a  well  sunk  in  the  northern  part  of 
the  area: 

Feet. 

Earth o    to      4 

Tripoli 4  20 

Stiff  red  clay 20  21^ 

Mixed  chert,  clay,  and  ocher 21^         40 

Cherty  limestone 40  93 

Cherty  limestone  bearing  galena 93         103 

Limestone 103         128 

Limestone  bearing  sphalerite  and  galena 128         136 

Soft  magnesian  limestone _ 136         173 

The  tripoli  is  everywhere  underlain  by  a  relatively  thin  bed  of 
stiff  red  clay,  and  also  traversed  in  every  direction  by  seams  of  the 
same  material  from  i  to  2  inches  thick.  These  seams  and  other 
joints  divide  the  rock  into  masses  which  vary  in  size  up  to  30  inches 
or  more  in  diameter.  Microscopic  examinations  as  given  by  Hovey 
show  the  rock  to  contain  no  traces  of  organic  remains,  but  to  be 
made  up  of  faintly  doubly  refracting  chalcedonic  particles  from  o.oi 
to  0.03  millimeter  in  diameter.  The  chemical  composition,  as 
shown  from  analysis  by  Prof.  W.  H.  Seaman,  is  as  follows: 

1  Bulletin  No.  340,  U.  S.  Geological  Survey,  1908,  p.  433. 

2  Scientific  American  Supplement,  July  28,  1894,  p.  15487. 


THE  NON-METALLIC  MINERALS. 


Constituents. 

Per  Cent. 

Silica  (SiO2)  

98.  loo 

Alumina  (A12O3) 

o  24.0 

Iron  oxide  (FeO  and  Fe2O3)  .... 
Lime  (CaO) 

0.270 
o  184. 

Soda  (Na2O)       .... 

o  230 

Water  (ignition)  

u.^<_> 

I    IOO 

Organic  matter  

o  008 

100.192 

The  material  boiled  in  a  10  per  cent  solution  of  caustic  soda  for 
three  hours,  yielded  7.28  per  cent  soluble  silica. 

Aside  from  its  use  as  a  filter  the  rock  is  crushed  between  buhr- 
stones,  bolted,  and  used  as  a  polishing  powder.  To  a  small  extent  it 
has  been  used  in  the  form  of  thin  slabs  for  blotting  purposes,  for 
which  it  answers  admirably,  owing  to  its  high  absorptive  property, 
but  is  somewhat  objectionable  on  account  of  its  dusty  character. 
The  view  (Plate  III)  shows  the  character  of  a  quarry  of  this  material 
as  now  worked  by  the  American  Tripoli  Company  at  Seneca,  in 
Newton  County. 

Diatomaceous  or  infusorial  earth,  as  it  is  sometimes  wrongly 
called,  is,  when  pure,  a  soft,  pulverulent  material,  somewhat  resem- 
bling chalk  or  kaolin  in  its  physical  properties,  and  of  a  white  or 
yellowish  or  gray  color.  Chemically  it  is  a  variety  of  opal  (see  analy- 
ses on  p.  72). 

Origin  and  occurrence  of  deposits. — Certain  aquatic  forms  and  plant 
life  known  as  diatoms,  which  are  of  microscopic  dimensions  only, 
have  the  power  of  secreting  silica  in  the  same  manner  as  mollusks 
secrete  carbonate  of  lime,  forming  thus  their  tests  or  shells.  On 
the  death  of  the  plant  the  siliceous  tests  are  left  to  accumulate  on  the 
bottom  of  the  lakes,  ponds,  and  pools  in  which  they  lived,  form- 
ing in  time  beds  of  very  considerable  thickness,  which,  however, 
when  compared  with  other  rocks  of  the  earth's  crust,  are  really  of 
insignificant  proportions.  Like  many  other  low  organisms  the 
diatoms  can  adapt  themselves  to  a  wide  range  of  conditions.  They 
are  wholly  aquatic,  but  live  in  salt  and  fresh  water  and  under  widely 
varying  conditions  of  depth  and  temperature.  They  may  be  found 
in  living  forms  in  almost  any  body  of  comparatively  quiet  water 
in  the  United  States.  The  exploring  steamer  Challenger  dredged 


OXIDES.  71 

them  up  in  the  Atlantic  from  depths  varying  from  1,260  to  1,975 
fathoms,  and  from  latitudes  well  toward  the  Antarctic  Circle.  Mr. 
Walter  Weed,  of  the  U.  S.  Geological  Survey,  has  recently  reported 
them  as  living  in  abundance  in  the  warm  marshes  of  the  Yellow- 
stone National  Park,  while  Dr.  Blake  reported  finding  over  50 
species  in  a  spring  in  the  Pueblo  Valley,  Nevada,  which  showed  a  tem- 
perature of  163°  F. 

Although  beds  of  diatomaceous  earth  are  still  in  process  of  forma- 
tion, and  in  times  past  have  been  formed  at  various  epochs,  the 
Tertiary  period  appears  for  some  reason  to  have  been  peculiarly 
fitted  for  the  growth  and  preservation  of  these  organisms,  and  all  of 
the  known  beds  of  any  importance,  both  in  America  and  foreign 
countries,  are  of  Tertiary  Age.  The  best  known  of  the  foreign 
deposits  is  that  of  Bilin,  in  Bohemia.  This  is  some  14  feet  in  thick- 
ness. When  it  is  borne  in  mind  that,  according  to  the  calculations 
of  Ehrenberg,  every  cubic  inch  of  this  contains  not  less  than  40,000,- 
ooo  independent  shells,  one  stands  aghast  at  the  mere  thought  of  the 
myriads  of  these  little  forms  which  such  a  bed  represents.  Some  of 
the  deposits  in  the  United  States  are,  however,  considerably  larger 
than  this.  What  is  commonly  known  as  the  Richmond  bed  extends 
from  Herring  Bay,  on  the  Chesapeake,  Maryland,  to  Petersburg, 
Virginia,  and  perhaps  beyond.  This  is  in  some  places  not  less  than 
30  feet  in  thickness,  though  very  impure.  Near  Drakesville,  iri 
New  Jersey,  there  occurs  a  smaller  deposit,  covering  only  some  3 
acres  of  territory  to  a  depth  of  from  i  to  3  feet.  Some  of  the  largest 
deposits  known  are  in  the  West.  Near  Socorro,  in  New  Mexico, 
there  is  stated  to  be  a  deposit  of  fine  quality  which  crops  out  in  a 
single  section  some  6  feet  in  thickness  for  a  distance  of  1,500  feet. 

Geologists  of  the  fortieth-parallel  survey  reported  abundant  de- 
posits in  Nevada,  one  of  which,  in  the  railroad  cutting  west  of  Reno, 
showed  a  thickness  not  less  than  300  feet,  of  a  pure  white,  pale 
buff,  or  canary-yellow  color.  Along  the  Pitt  River,  in  California, 
there  is  stated  to  be  a  bed  extending  not  less  than  16  miles,  and  in 
some  places  over  300  feet  thick  (see  Plate  IV).  In  the  northern 
part  of  Santa  Barbara  County  the  earth  occurs  in  quantities  which 
are  seemingly  truly  inexhaustible.  In  the  region  about  Lompoc, 
south  of  the  Santa  Inez  River,  beds  are  exposed  over  an  area  of  at 
least  3  square  miles,  and  which  have,  in  places,  a  thickness  of 


THE  NON-METALLIC  MINERALS. 


several  hundred  feet.1  Four  miles  west  of  Lompoc  1,000  feet  in 
thickness  of  beds  are  exposed,  and  in  the  Burton  Mesa  the  "pure 
diatomaceous  earth"  is  stated  to  be  2,000  feet  in  thickness.  Numer- 
ous other  localities  are  mentioned  where  the  material  is  almost  equally 
abundant.2  Near  Linkville,  Klamath  County,  Oregon,  there  occurs 
a  deposit  which  has  been  traced  for  a  distance  of  10  miles,  and  shows 
along  the  Lost  River  a  thickness  of  40  feet.  Beds  are  known  also 
to  occur  in  Idaho,  near  Seattle,  in  Washington,  and  doubtless  many 
more  yet  remain  to  be  discovered.  A  deposit  of  unknown  extent, 
pure  white  color,  and  almost  pulp-like  consistency,  has  been  worked 
in  South  Beddingham,  Maine.  Others  of  less  purity  occur  near 
South  Framington,  Massachusetts,  Lake  Umbagog,  New  Hamp- 
shire, at  Whitehead  Lake,  Herkimer  County,  New  York,  and  at 
Grand  Manan,  New  Brunswick. 

Chemical  composition. — As  already  intimated,  this  earth  is  of  a 
siliceous  nature,  and  samples  from  widely  separated  localities  show 
remarkable  uniformity  in  composition.  Of  the  following  analyses, 
No.  I  is  from  Lake  Umbagog,  New  Hampshire,  No.  II  from  Morris 
County,  New  Jersey,  and  No.  Ill  from  Pope's  Creek,  in  Maryland. 
As  will  be  noted,  the  silica  percentage  is  nearly  the  same  in  all. 


Constituents. 

I. 

II. 

III. 

Silica      .... 

80    qi 

80  66 

81   zi 

Alumina.  

=^.80 

3  84 

•7      4.7 

Iron  oxides 

I    O3 

Lime 

O     T.X. 

o  ?8 

•o4 
2    6l 

Soda 

Potash 

1  **rO 

i   16 

Water  and  organic  matter.  .  .  . 

I2.O3 

14.01 

6.04 

The  substance  may  therefore  be  regarded  as  a  variety  of  opal. 

Uses. — The  main  use  of  diatomaceous  earth  is  for  a  polishing 
powder.  It  is,  however,  an  excellent  absorbent,  and  has  been  utilized 
to  mix  with  nitroglycerine  in  the  manufacture  of  dynamite.  It  has 

1  A  block  of  this  material  some  5  feet  in  diameter  among  the  geological  col- 
lections of  the  National  Museum  is  reported  as  consisting  of  some   75  per  cent  of 
diatoms,  and   25  per  cent  of  sponge  spicules  and  radiolaria.     The  most  abundant 
forms  among  the  diatoms  are  Coscinodiscus  robustus,  Actinoptychus  undulatus,  and 
Ralfeii,  two  species  of  Raphoneus,  Biddulphia  aurita,  and  an  undetermined  species 
of  Synedra. 

2  Bulletin  No.  315,  U.  S.  Geological  Survey,  1906,  p.  438. 


PLATE    IV. 

Bed  of  Diatom  Earth,  Great  Bend  of  Pitt  River,  Shasta  County,  California. 
[From  photograph  by  J.  S.  Diller,  U.  S.  Geological  Survey.] 

[Facing  page  72.] 


OXIDES. 


73 


•also  been  used  to  some  extent  in  the  preparation  of  the  soluble  silicate 
known  as  water  glass,  and  still  again  as  a  non-conductive  material 
for  steam  boilers,  etc.  The  demand  for  the  material  is  quite  small, 
not  nearly  equal  to  the  supply.  The  Maryland  and  Nevada  de- 
posits are  the  principal  ones  now  worked.  During  the  year  1897 
the  entire  output  was  about  3,000  tons,  valued  at  some  $30,400. 

2.    CORUNDUM    AND    EMERY. 

Corundum.  —  Composition,    sesquioxide    of    aluminum,  'A12O3, 
-=  oxygen,  47.1   per  cent;    aluminum,   52.9  per  cent.     In  crystals 


FIG.  13. — Corundum  crystals,  characteristic  forms. 
[U.  S.  National  Museum.] 

often  quite  pure,  but  frequently  occurring  associated  in  crystalline 
granular  masses  with  magnetic  iron,  and  often  more  or  less  altered 
into  a  series  of  hydrated  aluminous  compounds,  as  damourite.  The 
crystalline  form  of  the  mineral  is  hexagonal,  or  six-sided  in  outline, 
often  with  curved  sides  and  square  terminations,  giving  rise  to 
roughly  barrel-shaped  forms,  as  shown  in  Fig.  13. 


74  THE  NON-METALLIC  MINERALS. 

A  prominent  basal  cleavage  causes  the  crystals  to  break  readily 
with  smooth  flat  surfaces  at  right  angles  with  the  axis  of  elongation. 
The  massive  forms  frequently  show  a  nearly  rectangular  parting  or 
pseudo-cleavage. 

The  most  striking  physical  property  of  the  mineral  is  its  hard- 
ness, which  is  9  of  Dana's  scale.  In  this  respect  it  ranks  then  next 
to  the  diamond.  The  color  varies  from  white  through  gray,  brown, 
yellow,  blue,  pink,  and  red;  luster,  adamantine  to  vitreous;  specific 
gravity,  3.95  to  4.1.  The  highly  colored  transparent  red  and  blue 
forms  are  valuable  as  gems,  and  are  known  under  the  names  of 
ruby  and  sapphire.  The  consideration  of  these  forms  is  beyond  the 
limits  of  this  work. 

Occurrence. — Although  widespread  as  a  mineral,  corundum  un- 
mixed with  a  large  proportion  of  magnetite  (forming  emery)  has  been 
found  in  comparatively  few  localities  in  sufficient  abundance  to  be 
of  commercial  value.  The  most  important  deposits  known  in  the 
United  States  are  in  southwestern  North  Carolina,  the  Laurel 
Creek  region  of  northern  Georgia,  and  central  Montana.  Within 
a  few  years  corundum-bearing  syenites,  covering  an  area  of  many 
square  miles,  have  been  found  in  Renfrew,  Hastings,  and  Halberton 
counties  in  Ontario,  Canada. 

According  to  Pratt,  most  of  the  corundum  that  has  been  mined 
in  the  United  States  for  abrasive  purposes  has  been  obtained  from 
the  eastern  part  of  the  section,  where  it  is  associated  with  a  long  belt 
of  basic  magnesian  rocks  (peridotites)  extending  from  Tallapoosa 
in  east  central  Alabama,  to  Trenton,  New  Jersey,  with  disconnected 
outcrops  north  of  New  Jersey,  as  in  Connecticut,  Massachusetts, 
New  Hampshire,  and  Maine.  In  the  southern  portion  of  this  belt 
the  peridotites  have  reached  their  greatest  development,  in  some 
localities  outcropping  over  an  area  of  several  hundred  acres.  At 
Webster,  in  Jackson  County,  North  Carolina,  the  peridotite  occurs 
intrusive  in  the  hornblendic  gneiss,  the  corundum  occurring  in  great- 
est abundance  at  or  near  the  line  of  contact  between  the  two  rocks. 
Associated  with  the  corundum  are  nearly  always  at  this  locality  a 
series  of  secondary  minerals,  including  vermiculite,  chlorite,  and 
talcose,  and  serpentinous  materials. 

An  ideal  cross-section  of  one  of  the  corundum  contact  veins  at 


OXIDES. 


75 


Corundum  Hil1,  in  Macon  County,  is  shown  in  Fig.  14,  while  a  map 
of  the  country,  showing  the  character  of  the  surrounding  rocks, 
is  shown  in  Fig.  15.  The  mine  at  Corundum  Hill  has  been  until 
recently  one  of  the  most  important  in  the  country,  and  may  be 
described  in  some  detail  as  illustrating  the  mode  of  occurrence  of  the 
material.  The  formation  here  is  a  rather  blunt,  lens-shaped  mass 


FIG.  14. — Ideal  cross-section  of  a  corundum  contact  vein  at  Corundum  Hill  Mine, 
North  Carolina;  a,  fresh  and  unaltered  gneiss;  b,  decayed  gneiss;  c,  vermiculite; 
d,  green  chlorite;  e,  corundum -bearing  zone;  /.  green  chlorite,  g,  enstatitef  h,  taicose 
rock;  i,  clay;  /,  altered  dunite;  k,  unaltered  dunite. 

[U.  S.  Geological  Survey.] 

of  peridotite  (dunite)  exposed  over  an  area  of  about  10  acres.  A 
number  of  veins  have  been  worked,  but,  with  the  exception  of  the 
one  marked  "  Shaft "  on  the  map,  they  have  soon  pinched  out. 

Most  of  the  mining  has  been  done  on  the  south  side  of  this  for- 
mation, as  described  by  Pratt,  by  means  of  open  cuts,  and  later  by 
tunnels.  Plate  V  shows  the  entrance  to  this  tunnel,  with  the  peri- 
dotite on  the  left  and  the  gneiss  on  the  right  beyond  the  cut.  For 
nearly  the  whole  distance  of  the  southern  boundary  of  the  dunite 
formation  a  cut  has  been  made,  following  the  contour  of  the  hill. 
This  is  sometimes  wholly  within  the  gneiss,  and  at  other  times  wholly 
within  the  peridotite,  and  again  cutting  directly  across  the  contact. 
The  tunnels  are  all  to  the  left  of  the  cut,  and  have  encountered 
corundum  almost  continuously  for  a  distance  of  1,280  feet.1 

1  These  mines  have  now  11909)  been  for  several  years  abandoned. 


76 


THE  NON-METALLIC  MINERALS. 


The  materials  collected  from  the  mines  at  Corundum  Hill  are 
in  the  forms  known  as  block,  crystal,  and  sand  ores.  The  mean- 
ing of  the  terms  is  obvious.  A  small  amount  of  garnet  is  occasionally 
found  associated  with  the  corundum  in  the  vein  along  the  southern 
contact. 


SCALE 

100  ZOO          300         400  FEET 


FIG.  15. — Map  of  peridotite  formation  at  Corundum  Hill,  Macon  County,  N.  C. 
[U.  S.  Geological  Survey.] 

At  what  is  known  as  the  Buck  Creek,  or  Cullakeenee  Mine, 
about  20  miles  southwest  of  Franklin  in  this  same  county, 
corundum  is  -found  associated  with  a  compact  mass  of  peridotite, 
covering  about  three-quarters  of  a  square  mile,  forming  the  largest 
mass  that  is  known  in  the  Appalachian  belt.  A  topographic  map 
of  this  area,  showing  the  association  of  the  various  rocks,  is  shown 
in  Fig.  16. 


PLATE   V. 

Vein  between  Peridotite  and  Gneiss,  Corundum  Hill,  Macon  County,  North  Carolina, 
[After  J.  H.  Pratt,  Bulletin  No.  180,  U.  S.  Geological  Survey.] 

[Facing  page  76.] 


OXIDES. 


77 


The  vein  here  is  described  as  differing  from  most  of  the  corundum 
veins  in  the  peridotite  rocks  in  that  it  is  composed  essentially  of 
plagioclase  feldspar,  and  hornblende,  which  bear  a  relation  to  each 
other  similar  to  that  of  the  feldspar,  quartz,  and  mica  in  pegmatite 
dikes.  There  is  an  abundance  of  ore  at  this  mine,  but  it  has  been 
as  yet  unexploited,  owing  to  difficulty  of  transportation. 


CONTOUR  /NTCFfVAL  SOfEET 


FIG.  16. — Map  of  the  Buck  Creek  peridotite  area,  showing  the  relation  of  the  amphibo- 

lite  dikes. 
[U.  S.  Geological  Survey.] 

At  Laurel  Creek,  in  Georgia,  on  what  is  known  as  Pine  Moun- 
tain, in  Rabun  County,  there  is  a  large  outcrop  of  peridotite  covering 
several  hundred  acres,  along  the  contact  of  which  with  the  gneiss  large 
deposits  of  corundum  have  been  found.  Fig.  17  shows  the  relation  of 
the  gneiss  and  the  peridotite.  The  formation  here  occupies  two  small 
hills,  which,  on  account  of  their  rough  and  barren  nature — a  feature 
characteristic  of  regions  occupied  by  iron  magnesian  rocks — offer 
a  sharp  contrast  to  the  surrounding  country.  A  large  open  cut  on 
the  east  side  of  the  formation  follows,  for  the  most  part,  along  the 
contact  to  a  depth  of  some  200  feet.  (Plate  6,  Fig.  i.)  At  its  lower 
end  this  cut  encounters  what  is  known  as  the  Big  or  Dunite  Vein  of 


THE  NON-METALLIC  MINERALS. 


massive  corundum,  the  cut  having  followed  on  a  contact  vein  of 
crystallized  corundum.  Although  this  vein  is  near  the  contact  of 
the  peridotite  with  the  gneiss,  it  is  separated  from  the  same  by  a 
band  of  peridotite  and  a  small  vein  of  sand  corundum.  This  has 
been  one  of  the  most  famous  mines  in  the  country,  and  has  furnished 
ore  of  an  exceptionally  high  grade. 


COMTOUR  /NTCRVAL  SO  fffT 


FlG.  17. — Map  of  the  peridotite  formation  at  Laurel  Creek,  Rabun  County,  Georgia. 
[U.  S.  Geological  Survey.] 

A  large  part  of  the  corundum  that  has  been  found  in  Montana 
is  of  the  sapphire  variety,  and  is  used  as  gem  material.  Hence  its 
consideration  belongs  properly  to  a  treatise  on  gems.  But  at  one 
locality,  not  far  from  Bozeman,  in  Gallatin  County,  corundum,  in 
well-defined  hexagonal  crystals,  of  all  sizes  up  to  10  millimeters  in 
diameter  and  20  to  30  millimeters  in  length,  has  been  found  in 
considerable  quantity  in  an  igneous  rock  composed  essentially  of 
orthoclase  feldspar,  corundum,  and  biotite.  The  rock  has  at  times 


Fig.  i. — Corundum  Vein  at  Laurel  Creek,  Georgia. 
[After  J.  H.  Pratt,  Bulletin  No.  180,  U.  S.  Geological  Survey.] 


FIG.    2. — Bauxite  Bed,  Saline  County,  Arkansas. 
[From  photograph  by  C.  W.  Hayes,  U.  S.  Geological  Survey.] 

PLATE  VI. 

[Facing  page  78.] 


OXIDES.  79 

a  somewhat  gneissic  structure,  and  in  these  portions  the  corundum 
is  found  in  a  more  or  less  finely  divided  condition,  and  in  other 
portions,  where  the  rock  has  a  pegmatitic  character,  the  corundum 
is  coarsely  crystallized  and  surrounded  by  orthoclase.  The  per- 
centage of  corundum  is  quite  large.  The  colors  vary  from  bluish 
gray  to  almost  colorless. 

Near  the  entrance  of  Yogo  Gulch,  in  Fergus  County,  in  this 
same  State,  feldspathic  igneous  rocks  allied  to  the  minettes  have 
been  found  carrying  sapphires.  The  rock  occurs  in  the  form  of 
two  parallel  dikes  about  800  feet  apart,  which  can  be  followed  for 
over  a  mile  in  a  nearly  east-and-west  course,  their  general  width 
being  from  6  to  20  feet.  The  rock,  which  is  much  decomposed 
on  the  surface,  has  a  dark  gray,  decidedly  basic  appearance,  and 
is  very  tough.  The  sapphires  are  mainly  of  some  shade  of  blue,  and 
occur  in  the  form  of  sharp,  distinct  crystals.  The  material  is  used 
wholly  for  gem  purposes. 

In  Ontario,  Canada,  the  corundum  occurs  as  a  primary  constitu- 
ent of  syenite,  the  rocks  varying  from  a  normal  syenite  to  a  nepheline 
syenite  and  a  mica  syenite,  the  mineral  being  most  abundantly 
developed  in  the  normal  syenite.  The  rocks  occur  as  dikes  cutting 
through  the -gneisses,  the  corundum  existing  in  such  abundance  as  to 
average  perhaps  12  per  cent  of  the  entire  mass,  and  in  crystals  of 
all  sizes  up  to  50  millimeters  in  diameter.  The  principal  areas  thus 
far  discovered,  as  shown  in  the  accompanying  map  (Fig.  18),  occupy 
an  area  some  75  miles  in  length  extending  from  Renfrew  County 
westerly  through  Hastings  into  Haliburton,  with  smaller  areas  in 
Peterborough  and  Frontenac  counties. 

The  corundum  deposits  of  India  have  been  described  by  T.  H. 
Holland.1  The  mineral  here  occurs  in  a  matrix  of  deep  flesh-colored 
feldspar,  which  is  in  bands  or  lenticular  masses  and  has  associated 
with  it  often  a  considerable  portion  of  sillimanite,  rutile,  spinel, 
and  mica. 

Corundum  in  what  is  apparently  commercial  quantities  has 
been  reported  in  the  ranges  near  Mts.  Painter  and  Pitts  in  South 
Australia.  The  mineral  occurs  in  the  form  of  segregation  lumps, 

1  Geology  of  India,  Part  III,  Economic  Geology. 


8o  THE  NON-METALLIC  MINERALS. 

rough  hexagonal  crystals  and  irregular  shaped  masses  disseminated 
throughout  a  schistose  metamorphic  rock  consisting  mainly  of  black 
mica. 

Origin. — The  origin  of  the  corundum  in  the  occurrences  above 
noted  can  be  in  part  surmised  from  the  descriptions  which  have 
been  given.  It  is  evident  that,  in  the  majority  of  cases,  such  fesult 
from  the  direct  crystallization  of  aluminum  oxide  from  a  molten 
magma. 


FIG.  18. — Map  of  corundum  areas  of  Canada. 

Experimental  work  by  Morozewicz  l  has  shown  that  from  super- 
saturated alumina-silicate  magmas  deficient  in  the  alkalies,  lime, 
magnesia,  and  iron,  the  alumina  may  all  separate  out  as  corundum. 
With  increasing  amounts  of  the  alkalies  and  lime,  the  feldspars,  in 
varying  proportions,  may  appear.  The  presence  of  magnesia  and 
iron  is  likely  to  give  rise  to  minerals  of  the  spinel  group,  as  well. 
These  results  are  all  in  accord  with  Montana,  North  Carolina  and 
Canadian  occurrences  and  may  probably  be  considered  as  final. 

1  Tschermak's  Min.  u.  Petr.  Mittheil.,  XVIII,  1898. 


OXIDES. 


81 


The  sapphires  occurring  in  the  basic  rock  from  Yogo  Gulch, 
Montana,  are  regarded  by  Pirsson1  as  of  pyrogenic  origin,  that  is, 
as  resulting  from  the  direct  crystallization  of  the  oxide,  which  has 
in  this  case  been  derived  from  aluminous  material  dissolved  from 
shales  by  the  molten  rock  during  its  intrusion.  It  seems  most 
probable  that  the  Indian  corundum,  even  including  the  ruby  of 
Burmah,  is  of  secondary  origin — a  result  of  metamorphism. 

Emery. — The  rock  emery  takes  its  name  from  Cape  Emeri,  on 
the  island  of  Naxos,  where  it  occurs  in  great  abundance.  Mineral- 
ogically  it  has  been  regarded  by  various  authorities  as  either  a  mechan- 
ical admixture  of  corundum  and  magnetic  iron  ore  or  as  simply  a 
massive  iron  spinel — hercynite.  So  far  as  the  Naxos  emery  is  con- 
cerned, the  first  view  in  undoubtedly  correct,  the  two  minerals 
occurring  in  about  the  proportion  of  two  parts  of  corundum  to  one 
of  magnetite  and  other  minerals.  Physically  emery  is  a  massive, 
nearly  opaque,  dark-gray  to  blue  black  or  black  material,  with  a 
specific  gravity  of  4  and  hardness  of  8,  Dana's  scale,  breaking  with 
a  tolerably  regular  fracture,  and  always  more  or  less  magnetic. 

Chemically  the  material  is  quite  variable.  Below  are  the  results 
of  analyses  by  Dr.  J.  Lawrence  Smith,  from  whose  papers  on  the 
subject  these  notes  are  partially  compiled. 


Localities. 

Alumina. 

Iron.2 

Lime. 

Silica. 

Water. 

Kulah  | 

61.05 

27-J5 

1.30 

9-63 

2.OO 

Samos  

63-5° 

70.  10 

33-25 

22.21 

0.92 
0.62 

1.61 
4.00 

1.90 

2.IO 

Gumuch  ...                                     } 

60.  10 

33-2° 

0.48 

i.  80 

5-62 

Nicaria                                                •< 

77.82 

71.06 

8.62 

20.32 

1.  80 
1.40 

8.13 

4.12 

3»« 

2-53 

Ephesus.  .  . 

75-I2 
60  10 

13.06 

•7-2      2O 

0.72 
0    4.8 

6.88 
i  80 

3-i° 
«;  62 

44.01 

^O.2I 

3-1"? 

CQ    O2 

A  A       I  I 

-}    2£ 

Chester,  Massachusetts.  .  . 

e  I    02 

4.2    2^ 

54.6 

Id.    22 

IQ    31 

•**•;* 

e    48 

84    O2 

963 

0  -H-" 
4  81 

1  American  Journal  of  Science,  Vol.  IV,  1894,  p.  42. 

2  It  is  stated  that  the  American  Plate  Glass  companies,  while  accepting  an  emery 
carrying  as  high  as  60  per  cent  Fe2O3,  will  not  accept  this  in  the  form  of  an  artificial 
admixture    of    corundum    and    magnetite.      It    must    be    the    natural,   crystalline 
admixture. 


82  THE   NON-METALLIC  MINERALS. 

Geologically  emery,  like  corundum,  belongs  to  the  older  crystal- 
line rocks.  In  Asia  Minor  it  occurs  in  angular  or  rounded  masses 
from  the  size  of  a  pea  to  those  of  several  tons  weight,  embedded 
in  a  blue-gray  or  white  crystalline  limestone,  which  overlies  mica- 
ceous or  hornblendic  schists,  gneisses,  and  granites.  Superficial 
decomposition  has,  as  a  rule,  removed  more  or  less  of  the  more 
soluble  portions  of  the  limestone,  leaving  the  emery  nodules  in  a  red 
ferruginous  soil.  With  the  emery  are  associated  other  aluminous 
minerals  as  mentioned  below. 

According  to  Tschermak1  the  Naxos  emery  occurs  mostly  in  the 
form  of  an  iron-gray,  scaly  to  schistose,  rarely  massive,  aggregate 
consisting  essentially  of  magnetite  and  corundum,  the  latter  mineral 
being  in  excess.  In  addition  to  these  two  minerals  occur  hematite 
and  limonite,  as  alteration  products  of  the  magnetite.  Margarite, 
muscovite,  biotite,  tourmaline,  chloritoid,  diaspore,  disthene,  stauro- 
lite,  and  rutile  occur  as  common  accessories;  rarely  are  found 
spinel,  vesuvianite,  and  pyrite.  Under  the  microscope  he  finds  the 
emery  rock  to  show  the  corundum  in  rounded  granules  and  some- 
times well-defined  crystals  with  hexagonal  outlines,  particularly  in 
cases  where  single  individuals  are  embedded  in  the  iron  ores.  (Plate 
VII,  Fig.  2.)  In  many  cases,  as  in  the  emery  of  Krenino  and 
Pesulas,  the  granules  are  partially  colored  blue  by  a  pigment  some- 
times irregularly  and  sometimes  zonally  distributed.  The  corundum 
grains,  which  vary  in  size  between  0.05  mm.  and  0.52  mm.  (averaging 
about  0.22  mm.),  are  very  rich  in  inclosures  of  the  iron  ores,  largely 
magnetite  in  the  form  of  small,  rounded  granules.  The  quantity  of 
these  is  so  great  as  at  times  to  render  the  mineral  quite  opaque, 
though  at  times  of  such  dust-like  fineness  as  to  be  translucent  and  of 
a  brownish  color.  The  larger  corundums  are  often  injected  with 
elongated,  parallel-lying  clusters  or  groups  of  the  iron  ores,  as 
shown  in  Fig.  3,  of  the  plate  from  Tschermak's  paper,  and  are  sur- 
rounded by  borders  of  very  minute  zircons.  The  iron  ore,  as  noted 
above,  is  principally  magnetite,  but  which,  by  hydration  and  oxida- 
tion, has  given  rise  to  abundant  limonite.  The  magnetites  are  in 
the  form  of  rounded  granules  and  dust-like  particles,  and  also  at 

1  Mineralogische  und  Petrographische  Mittheilungen,  XIV,  1894,  p.  313. 


PLATE   VII. 
Microstructure  of  Emery. 
[After  Tschermak,  Min.  u.  Pet.  Mittheil.,  XIV,  Part  IV.] 

[Facing  page  82.] 


OXIDES  83 

times  in  well-defined  octahedrons.  In  their  turn  the  magnetites  also 
inclose  particles  of  corundum  very  much  as  the  metallic  iron  of 
meteorites  of  the  pallasite  group  inclose  the  olivines,  and  as  shown 
in  Fig.  4  of  the  plate. 

The  following  account  of  these  deposits  and  the  method  of  work- 
ing is  by  A.  Gobantz : l 

Naxos,  the  largest  of  the  Cyclades  Islands,  is  remarkable  as  being 
one  of  the  few  localities  in  the  wrorld  producing  emery  on  a  large 
scale;  the  deposits,  which  are  of  an  irregularly  bedded  or  lenticular 
form,  being  mostly  concentrated  on  the  mountains  at  the  northern 
end  of  the  islands,  the  most  important  ones  being  in  the  immediate 
vicinity  of  the  village  of  Bothris.  The  island  is  principally  made  up 
of  Archaean  rocks,  divisible  into  gneiss  and  schist  formations,  the 
latter  consisting  of  mica  schists  alternating  with  crystalline  lime- 
stones. The  lenticular  masses  of  emery,  which  are  quite  variable 
in  size,  ranging  in  length  from  a  few  feet  to  upward  of  100  yards 
and  in  maximum  thickness  from  5  to  50  yards,  are  closely  asso- 
ciated with  the  limestones,  and,  as  they  follow  their  undulations, 
they  vary  greatly  in  position,  lying  at  all  kinds  of  slope,  from  hori- 
zontal to  nearly  vertical.  Seventeen  different  deposits  have  been 
discovered  and  worked  at  different  times.  These  range  over  con- 
siderable heights  from  180  to  700  meters  above  sea-level,  the  largest 
working,  that  of  Malia,  being  one  of  the  lowest.  This  important 
deposit  covers  an  area  of  more  than  30,000  square  meters,  extending 
for  about  500  meters  in  length  with  a  height  of  more  than  50  meters. 
This  was  worked  during  the  Turkish  occupation,  and  it  has  supplied 
fully  one-half  of  all  the  emery  exported  since  the  formation  of  the 
Greek  Kingdom.  The  highest  quality  of  mineral  is  obtained  from 
two  comparatively  thin  but  extensive  deposits  at  Aspalanthropo  and 
Kakoryakos,  which  are  435  meters  above  the  sea-level.  The  mineral 
is  stratified  in  thin  bands  from  i  to  2  feet  in  thickness,  crossed 
by  two  other  systems  of  divisional  planes,  so  that  it  breaks  into  nearly 
cubical  blocks  in  the  working.  The  floor  of  the  deposit  is  invariably 


1  Oesterreichische  Zeitschrift  fur  Berg-  und  Hiittenwesen,  XLII,  p.  143.  Abstract 
in  the  Minutes  and  Proceedings  of  the  Institute  of  Civil  Engineers,  CXVII,  pp.  466- 
468. 


84  THE  NON-METALLIC  MINERALS. 

crystalline  limestone,  and  the  roof  a  loosely  crystalline  dolomite 
covered  by  mica  schist.  The  underlying  limestones  are  often 
penetrated  by  dikes  of  tourmaline  granite,  which  probably  have 
some  intimate  connection  with  the  origin  of  the  emery  beds  above 
them. 

The  working  of  the  deposits  is  conducted  in  an  extremely  primi- 
tive fashion.  The  rock  is  first  broken  by  fire-setting.  A  piece  of 
ground  about  5  feet  broad  is  cleared  from  loose  material,  and  a 
pile  of  brushwood  heaped  against  it  and  lighted.  This  burns  out 
in  about  twenty-four  or  thirty  hours,  when  water  is  thrown  upon  the 
heated  rock  to  chill  it  and  develop  fractures  along  the  secondary 
divisional  planes  in  the  mass  of  emery,  and  so  facilitate  the  breaking 
up  and  removal  of  the  material.  Sometimes  a  crack  is  opened 
out  by  inserting  a  dynamite  cartridge,  but  the  regular  use  of  explosives 
is  impossible  as,  owing  to  the  hardness  of  the  mineral,  it  can  not  be 
bored  with  steel  tools. 

The  only  deposits  of  emery  at  present  worked  in  the  United 
States  occur  on  what  are  known  as  North  and  South  Mountains, 
near  Chester,  in  Hampden  County,  Massachusetts,  and  Peekskill 
in  Westchester  County,  New  York.  The  Chester  deposits  were 
first  described  by  Dr.  C.  T.  Jackson  (in  1864)  and  developed  by 
Dr.  H.  S.  Lucas,  the  material  being  at  first  regarded  as  mainly 
magnetite  and  worked  as  an  iron  ore. 

The  vicissitudes  of  the  operations  here,  like  those  of  the  chromite 
deposits  near  Baltimore,  form  one  of  the  interesting  chapters  in  the 
history  of  mining  operations  in  the  United  States,  but  which  can  not 
be  here  touched  upon.  ^ 

The  deposits  have  been  frequently  described,  as  noted  in  the- 
bibliography,  the  facts  which  are  here  given  being  derived  mainly 
from  the  recent  works  of  B.  K.  Emerson  and  J.  H.  Pratt.  The 
country  rock  is  schistose  epidotic-amphibolite  of  doubtful  origin,  but 
which  Pratt  thinks  may  be  an  altered  eruptive.  The  emery-bearing 
veins  conform  in  a  general  way  with  the  winding  of  the  schist,  and 
have  a  strike  of  approximately  north  20°  east,  south  20°  west,  dip- 
ping to  the  eastward  at  an  angle  of  some  70°.  As  first  shown, 
where  cut  by  the  Westfield  River,  the  vein  is  very  narrow,  but 
widens  rapidly  to  the  north,  attaining  a  width  of  17  feet,  of  which 


OXIDES. 


some  10  feet  are  emery,  the  remainder  being  mainly  magnetite. 
The  vein,  or  bed,  cuts  through  both  North  and  South  Mountains, 
and  has  been  traced  a  distance  of  some  5  miles,  though  the  emery 
is  not  continuous  for  the  entire  distance.  It  can,  however,  be  traced 
by  means  of  streaks  of  chlorite  (corundophillite)  which  almost  invari- 
ably accompany  it.  Other  characteristic  associates  are  the  above  no  ted 
margarite  and  magnetite, 
talc,  and  black  tourma- 
line, the  vein  material  it- 
self being  described  as  a 
chloritic  magnetite  con- 
taining in  abundance 
bronze-colored  grains  of 
emery  and,  along  the 
borders  of  the  thicker 
portion  of  the  main 
vein  and  of  the  eastern 
vein,  a  considerable 
quantity  of  brown-black 
tourmaline  in  delicate 
stellate  forms.  The  part 
of  the  vein  rich  in  emery 
shows  the  material  in  the 
form  of  a  dark  gray, 
nearly  black  massive 
rock,  throughout  which 
the  corundum  is  dis- 
seminated in  the  form 
of  small  crystals,  some- 
times 5  to  15  millimeters 
color. 

Six  mines  have  from  time  to  time  been  opened  on  this  deposit, 
as  shown  in  Fig.  19.  At  the  Melvin  Mine  the  vein  varies  from 
6  to  16  feet  in  width.  A  cross-section  of  the  Old  Mine  is  given 
in  Fig.  20.  The  limits  of  the  deposit  as  given  by  Emerson  are: 
Length,  4  miles;  depth,  750  feet  (above  the  level  of  the  brook), 
and  with  an  average  width  of  4  feet. 


FIG.  19. — Map  showing  location  of  emery  deposits 
at  Chester,  Massachusetts. 
[U.  S.  Geological  Survey.] 


in    diameter    and    of   a   rich    bronze 


86 


THE  NON-METALLIC  MINERALS. 


The  origin  of  this  ore 
has,  naturally,  been  a  mat- 
ter of  some  speculation. 
Emerson  regards  it  as  most 
probable  that  the  emery- 
magnetite  material  was 
originally  a  deposit  of  lim- 
onite,  which  was  formed 
by  the  replacement  of  lime- 
stone, and  into  which  alu- 
mina was  carried  by  infil- 
trating solutions  and  de- 
posited as  allophane  and 
gibbsite,  ultimately  altered 
into  corundum  and  mag- 
netite by  metamorphism. 
Pratt,  on  the  other  hand, 
regards  the  amphibolite  as 
probably  an  altered  eruptive 
rock,  and  argues  that  the 
magnetite  and  corundum 
are  both  segregations  of 
basic  materials  from  the 
igneous  magma,  i.e.,  are 
products  of  magmatic  dif- 
ferentiation. 

The  Peekskill  emery  oc- 
curs in  the  form  of  a  hard, 
dark  gray  to  nearly  black 
rock  which  the  microscope 
has  shown  to  cpnsist  es- 
sentially of  corundum,  spi- 
nel, and  magnetite,  the  first 
named  in  varying  propor- 
tions up  to  50  per  cent  of 
the  mass.  It  is  associated 
in  the  form  of  lenses  and 


....'.?&.. 


....£...,.#?.,.. 


1° 


I     §    .1 

I    o    5b 

•4  fi  S 


bo  t/ 


OXIDES.  87 

bands,  with  intrusive  rocks — gabbros — from  which  it  was  doubtless 
derived  by  a  process  of  magmatic  segregation.  The  extent  of  the 
individual  deposits  is  very  irregular  and  unreliable.  The  mines 
are  all  open  cuts  located  on  natural  outcrops,  the  yield  from  any 
one  opening  being  rarely  over  100  tons  and  frequently  much  less. 
The  annual  output  is  but  500  to  700  tons,  and  the  material 
regarded  commercially  as  inferior  to  that  of  Naxos,  but  well 
adapted  for  emery  wheels  and  like  purposes. 

Sources. — The  chief  foreign  commercial  sources  of  emery  are  those 
of  Gumuch-dagh,  between  Ephesus  and  the  ancient  Tralles:  Kulah, 
and  near  the  river  Hermes  in  Asia  Minor;  and  the  island  of  Naxos, 
whence  it  is  quarried  and  shipped  from  Smyrna,  in  part  as  ballast, 
to  all  parts  of  the  world.  The  chief  commercial  source  in  the 
United  States,  or  indeed,  in  North  America,  is  Chester,  Massachu- 
setts, and  Peekskill,  New  York,  as  above  noted.  The  island  of 
Naxos  is  stated  to  have  for  several  centuries  furnished  almost 
exclusively  the  emery  used  in  the  arts,  the  material  being  chiefly 
obtained  from  loose  masses  in  the  soil.  The  mining  at  Kulah 
and  Gumuch-dagh  was  begun  about  1847,  and  at  Nicaria  in 
1850. 

Uses. — In  preparing  for  use,  the  mineral,  after  being  dug  from  the 
soil  or  blasted  from  the  parent  ledge,  is  pulverized  and  bolted  in 
various  grades,  from  the  finest  flour  to  a  coarse  sand,  the  excess  of 
magnetite,  where  such  exists,  being  extracted  by  means  of  an  electro- 
magnet. The  commercial  prices  vary  according  to  grade  from  3  to 
10  cents  a  pound. 

The  chief  uses  of  both  emery  and  corundum,  as  is  well  known, 
are  in  the  form  of  powder  by  plate-glass  manufacturers,  lapidaries, 
and  stone  workers;  as  emery  paper,  or  in  the  form  of  solid  disks 
made  from  the  crushed  and  bolted  mineral  and  cement,  known 
commercially  as  emery  wheels.  The  great  toughness  and  superior 
cutting  power  of  these  wheels  render  them  of  service  in  grinding 
glass,  metals,  and  other  hard  substances,  where  the  natural  stone  is 
quite  inefficient. 

An  "emery"  recently  put  upon  the  market  consists  of  an  artificial 
admixture  of  Canadian  corundum  and  magnetite.  The  cutting 
power  of  the  mixture  is  less  than  that  of  the  natural  emery,  where 


88  THE   NON-METALLIC  MINERALS. 

the  two  substances  are  so  closely  intercrystallized,  and  among  those 
who  know,  it  will  rarely  be  accepted  as  an  equivalent. 
(See  further  under  Grind-  and  Whetstones,  p.  400.) 

BIBLIOGRAPHY  OF  CORUNDUM  AND  EMERY. 

J.  LAWRENCE  SMITH.     Memoir  on  Emery — First  part — On  the  Geology  and  Miner- 
alogy of  Emery,  from  observations  made  in  Asia  Minor. 

American  Journal  of  Science,  X,  1850,  p.  354. 
Memoir  on  Emery — Second  Part — On  the  Minerals  associated  w.t     Emery. 

American  Journal  of  Science,  XI,  1851,  p.  53. 

CHARLES  T.  JACKSON.     Discovery  of  Emery  in  Chester,  Hampden  County,  Massa- 
chusetts. 

Proceedings  of  the  Boston  Society  of  Natural  History,  X,  1864,  p.  84. 

American  Journal  of  Science,  XXXIX,  1865,  p.  87. 

CHARLES  U.  SHEPARD.     A  Description  of  the  Emery  Mine  of  Chester,  Hampden 
County,  Massachusetts. 

Pamphlet,   16  pp.,  London,  1865. 

J.  LAWRENCE  SMITH.     On  the  Emery  Mine  of  Chester,  Hampden  County,  Massachu- 
setts. 

American  Journal  of  Science,  XLII,  1866,  pp.  83-93. 

Original  Researches  in  Mineralogy  and  Chemistry,  1884,  p.  in. 
C.  W.  JENKS.     Corundum  of  North  Carolina. 

American  Journal  of  Science,  III,  1872,  p.  301. 
CHARLES  U.  SHEPARD.     On  the  Corundum  Region  of  North  Carolina  and  Georgia. 

American  Journal  of  Science,  IV,  1872,  pp.  109  and  175. 
FREDERICK  A.  GENTH.     Corundum,  its  Alterations  and  Associated  Minerals. 

Proceedings  of  the  American  Philosophical  Society,  XIII,  1873,  p.  361. 
C.  W.  JENKS.     Note  on  the  occurrence  of  Sapphires  and  Rubies  in  situ  with  Corun- 
dum, at  the  Culsagee  Mine,  Macon  County,  North  Carolina. 

Quarterly  Journal  of  the  Geological  Society,  XXX,  1874,  p.  303. 
W.  C.  KERR.     Corundum  of  North  Carolina. 

Geological  Survey  of  North  Carolina,  I,  Appendix  C,  1875,  p.  64. 
C.  D.  SMITH.     Corundum  and  its  Associate  Rocks. 

Geological  Survey  of  North  Carolina,  I,  Appendix  D,  1875,  pp.  91-97. 
R.  W.  RAYMOND.     The  Jenks  Corundum  Mine,  Macon  County,  North  Carolina. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  VII,  1878,  p.  83. 
J.  WELCOX.     Corundum  in  North  Carolina. 

Proceedings,  Academy  of  Natural  Sciences,  Philadelphia,  XXX,  1878,  p.  223. 
F.  A.  GENTH.     The  so-called  Emery-ore  from  Chelsea,  Bethel  Township,  Delaware 
County,   Pennsylvania. 

Proceedings,  Academy  of  Natural  Sciences,  Philadelphia,  XXXII,  1880,  p.  311, 
C.  D.  SMITH.     Corundum. 

Geological  Survey  of  North  Carolina,  II,  1881,  p.  42. 
F.  A.  GENTH.     Contributions  to  Mineralogy. 

Proceedings  of  the  American  Philosophical  Society,  XX,  1882. 


OXIDES  89 

T.  M.  CHATARD.     Corundum  and  Emery. 

Mineral  Resources  of  the  United  States,  1883-84,  p.  714. 
The  Gneiss-Dunyte  Contacts  of  Corundum  Hill,  North  Carolina,  in  relation 

to  the  Origin  of  Corundum. 

Bulletin  No.  42,  U.  S.  Geological  Survey,  1887,  p.  45. 
G.  H.  WILLIAMS.     Norites  of  the  "Cortlandt  Series." 

American  Journal  of  Science,  XXXIII,  1887,  p.  194. 
F.  A.  GENTH.     Contributions  to  Mineralogy.     • 

American  Journal  of  Science,  XXXIX,  1890,  p.  47. 

A.  GOBAUTZ.     The  Emery  Deposits  of  Naxos. 

Engineering  and  Mining  Journal,  LVIII,  1894,  p.  294. 
FRANCIS  P.  KING.     Corundum  Deposits  of  Georgia. 

Bulletin  No.  2,  Geological  Survey  of  Georgia,  1894,  133  pp. 
T.  D.  PARET.     Emery  and  Other  Abrasives. 

Journal  of  the  Franklin  Institute,  CXXXVII,  1894,  pp.  353,  421. 
J.  C.  TRAUTWINE.     Corundum  with  Diaspore,  Culsagee  Mine,  North  Carolina. 

Journal  of  the  Franklin  Institute,  XCIV,  p.  7. 
T.  VOLNEY  LEWIS.     Corundum  of  the  Appalachian  Crystalline  Belt. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXV,  1895,  p.  852. 
Th£  Corundum  Lands  of  Ontario. 

Canadian  Mining  Review,  XVII,  1898,  p.  192. 

B.  K.  EMERSON.     Monograph,  XXIX,  U.  S.  Geological  Survey,  1898,  p.  117. 
J.  H.  PRATT.     Bulletin  No.  180,  U.  S.  Geological  Survey,  1901. 

H.  C.  MAGNUS.     Twenty-third  Annual  Report  State  Geologist  of  New  York,  1903. 
F.  D.  ADAMS  and  A.  E.  BARLOW.     Nephelin  and  Associated  Alkali  Syenites  of 
Eastern  Ontario. 

Transactions  of  the  Royal  Society  of  Canada,  II,  1908-09. 


3.   BAUXITE. 

Composition. — AhOa^HbO,  =  alumina,  73. 9 per  cent;  water,  26.1 
per  cent.  Commonly  impure  through  the  presence  of  iron  oxides, 
silica,  lime,  and  magnesia.  Color,  white  or  gray  when  pure,  but 
yellowish,  brown,  or  red  through  impurities.  Specific  gravity,  2.55; 
structure,  massive,  or  earthy  and  clay-like.  According  to  Hayes  1 
the  bauxites  of  the  Southern  United  States  show  considerable  variety 
in  physical  appearance,  though  generally  having  a  pronounced 
pisolitic  structure.  The  individual  pisolites  vary  in  size  from  a 

1  The  Geological  Relations  of  the  Southern  Appalachian  Bauxite  Deposits. 
Transactions  of  the  American  Institute  of  Mining  Engineers,  XXIV,  1894,  pp. 
250-251 


90  THE  NON-METALLIC  MINERALS. 

fraction  of  a  millimeter  to  3  or  4  centimeters  in  diameter,  although 
most  commonly  the  diameter  is  from  3  to  5  millimeters.  The  matrix 
in  which  they  are  embedded  is  generally  more  compact  and  also 
lighter  in  color.  The  larger  pisolites  are  composed  of  numerous 
concentric  shells,  separated  by  less  compact  substance  or  even  open 
cavities,  and  their  interior  portions  readily  crumble  to  a  soft 
powder. 

In  thin  sections  the  ore  is  seen  to  be  made  up  of  amorphous 
flocculent  grains.  The  matrix  in  which  the  pisolites  are  embedded 
may  be  composed  of  this  flocculent  material  segregated  in  an  irregulary 
globular  form  or  in  compact  oolites,  with  sharply  denned  outlines. 
Or  both  forms  may  be  present,  the  compact  oolites  being  embedded 
in  a  matrix  composed  of  the  less  definite  bodies.  In  some  cases  the 
interstices  between  the  oolites  are  filled  either  wholly  or  in  part  with 
silica,  apparently  a  secondary  deposition. 

The  pisolites  also  show  considerable  diversity  in  structure.  In 
some  cases  they  are  composed  of  the  same  flocculent  grains  as 
the  surrounding  matrix,  from  which  they  are  separated  by  a  thin 
shell  of  slightly  denser  material.  This  sometimes  shows  a  number 
of  sharply  defined  concentric  rings,  and  is  then  distinctly  separated 
from  the  matrix  and  the  interior  portion  of  the  pisolite.  The  latter 
is  also  sometimes  composed  of  imperfectly  defined  globular  masses, 
and  in  other  cases  of  compact,  uniform,  and  but  slightly  granular 
substance.  It  is  always  filled  with  cracks,  which  are  regularly  radial 
and  concentric,  in  proportion  as  the  interior  substance  has  a  uniform 
texture.  Branching  from  the  larger  cracks,  which,  as  a  rule,  are 
partially  filled  with  quartz,  very  minute  cracks  penetrate  the  inter- 
vening portions.  Thus  the  pisolites  appear  to  have  lost  a  portion 
of  their  substance,  so  that  it  no  longer  fills  the  space  within  the  outer 
shell,  but  has  shrunk  and  formed  the  radial  cracks.  No  analyses 
have  been  made  of  the  different  portions  of  the  pisolites  or  of  the 
pisolites  and  matrix  separately,  and  it  is  impossible  to  say  whether 
any  differences  in  chemical  composition  exist.  It  may  be  that  some 
soluble  constituent  has  been  removed  from  the  interior  of  the  pisolites, 
but  it  is  more  probable  that  the  shrinking  observed  is  due  wholly  to 
desiccation. 


OXIDES, 


Scattered  throughout  the  ground  mass  are  occasional  fragments 
of  pisolites,  whose  irregular  outlines  have  been  covered  to  varying 
depths  by  a  deposit  of  the  same  material  as  forms  the  concentric 
shells,  and  thus  have  been  restored  to  spherical  or  oval  forms. 

The  following  table  will  serve  to  show  the  wide  range  of  com- 
position of  bauxites  from  various  sources : 

COMPOSITION    OF    BAUXITES    FROM    VARIOUS    LOCALITIES. 


Localities. 

SiO2. 

Ti02. 

A12O3. 

Fe203. 

(ten) 
H20. 

(100°) 
H20. 

P203. 

Analyst. 

i.  Baux,  France: 
a.  Compact  variety  
b.   Pisiform  

2.8 

4.8 

3-i 

3-2 

57.6 
55-4 

30.3 
33-2 

69.3° 

76.90 
64.24 

50.85 
49.02 
50.92 
39-44 

45-94 
47-52 
41.38 
41  .00 

48.92 
52.21 
57.25 

25-3 
24.8 

34-9 
48.8 

22.90 

.  10 

2.40 

14.36 
12.90 
15-70 
2.27 

11.86 
19-95 

-85 
25-25 

2.14 

13-50 
3.21 

10 

1  1 

22 

8 
14 

15 
25 

27.03 
25.88 
27-75 
12.80 

21  .  2O 
23 
23 
20.43 

23.41 
27 

.8 
.6 

.  i 
.6 

.  10 

.80 
•74 

i  •  35 
•  93 

.85 

9.  20 

I  .  40 

-57 
.72 
•  65 

•45 

.72 



Deville. 
Do. 

Do. 
Do. 

Lill. 

Lang. 
Do. 
Liebreich. 
Dr.  Wm.  B. 

Phillips. 

Do. 
Do. 
Do 
W.  F.  Hille- 
brand. 
Do. 
Nichols. 
Do. 
Do. 

Prof.  H.  C. 
White 

c.   Hard     and     compact 
calcareous  paste 

2.   Calabres,  France  

2.0 
0.30 
2.  20 

6.  29 

5-14 

10.  27 

I  .  IO 

37.87 

18   67 

1.6 
3-4° 

4.00 

3-20 

3.  Thoronet,       France,       red 
variety  
4.  Villeveyrac,        Herault, 
France,   white   variety.  . 
5.  Wochein,  Germany  
6.   Langsdorf,  Germany: 
a.   Brownish  red  
b.   Light  red  
7.  Vogelsberg,  Germany  
8.  Cherokee  Co.  ,  Alabama.  .  . 

9.  Jacksonville.  Calhoun  Co., 

"!46 

.48 
.38 

a.   Red  

b    White 

7-73 

c     Red 

10.  25 
21.08 

2.  80 

2.53 

2.52 

3.52 

3    60 

Trace. 
Trace 

_r/.  White  ._  
10.  Floyd  Co.,  Georgia  
n           Do.  .  .  . 

12.          Do  
13.  Barnsley  estate,  Dinwood 
Station,  Georgia,  No.  7.  . 
14.  Pulaski  Co.,  Arkansas: 
a.  Black  

2.30 
I  .98 

10   13 

3-55 
2.38 

56.88 
61  .  25 

55-59 
57.62 
62.05 
46.40 
58.60 
55.64 
51  .90 

i  .49 
1.82 

6.08 
1.83 
1.66 
22.15 
9.11 
I.  OS 
3-  16 

.07 

31 

28 
28 
30.31 
26 
28 
27.62 
24.86 

•43 
•99 

•63... 

.68 
•  63 

b.          Do  
c.          Do  
d.  Red  

e           Do 

II  .48 
2  .  OO 
4.89 

3-34 
10.38 
16.76 

3-50 

3-50 
3-50 

::;::; 

f.          Do.  .  , 

g.          Do  

No.  i. — Contains  also  0.4  CaCOs.  No.  2. — 0.2  CaCOs.  No.  3.  — 12.7  CaCOs.  No.  5. — 
22.90  FeO  +  Fe2O3.  No.  6.— o.io  FeO  +  Fe2O3.  No.  7.— 0.85  CaO  0.38  MgO,  0.20  SO3. 
No.  8.— 0.35  FeO,  0.41  CaO,  o.n  MgO,  0.09  K2O.  0.17  Na2O,  trace  CO2.  No.  9.— FeO  not 
det.,  0.62  CaO,  trace  MgO,  o.n  K2O,  0.20  Na2O.  0.26  CO2.  No.  10.— 0.80  CaO,  0.16  MgO. 

Origin  and  mode  oj  occurrence. — The  mineral  received  its  name 
from  the  village  of  Baux  (or  Beaux1)  in  Southern  France,  where  a 
highly  ferriferous,  pisolitic  variety  was  first  found  and  described  by 
Berthier  in  1821.  The  origin  of  the  mineral,  both  here  and  elsewhere, 
has  been  a  matter  of  considerate  discussion.  The  following  notes 


1  Hence  the  au  should  receive  the  sound  of  long  o,  and  not  that  of  the  au  in  our 
word  haul. 


92  THE  NON-METALLIC  MINERALS. 

relative  to  the  foreign  occurrences  are  from  a  paper  by  R.  L. 
Packard:1 

The  geological  occurrence  of  the  bauxite  of  Baux  was  studied 
by  H.  Coquand  2  who  describes  the  mineral  as  of  three  varieties, 
pisolitic,  compact,  and  earthy.  The  pisolitic  variety  occurs  in  highly 
tilted  beds  alternating  with  limestones,  sandstones,  and  clays,  be- 
longing to  the  Upper  Cretaceous  period,  and  in  pockets  or  cavities 
in  the  limestone.  The  limestone  containing  the  bauxite  and  that 
adjacent  thereto  is  also  pisolitic,  some  nodules  being  as  large  as  the 
fist.  The  pisolitic  bauxite  has  sometimes  a  calcareous  cement, 
and  at  others  is  included  in  a  paste  of  the  compact  mineral.  Coquand 
supposed  that  the  alumina  and  iron  oxide  composing  the  bauxite 
were  brought  to  the  ancient  lake  bed  in  which  the  lacustrine  lime- 
stone was  formed,  by  mineral  springs,  which,  discharging  in  the 
bottom  of  the  lake,  allowed  the  alumina  and  iron  oxide  to  be  dis- 
tributed with  the  other  sediments.  In  some  cases  the  discharge 
occurred  on  land,  and  the  deposit  then  formed  isolated  patches. 
Sometimes  the  highly  ferriferous  mineral  predominates  over  the 
aluminous  (white),  at  others  diaspore  is  found  enveloping  the  red 
mineral,  while  in  other  cases  it  is  mixed  with  it,  predominating  largely 
and  sometimes  manganese  peroxide  replaces  ferric  oxide. 

M.  Ange3  describes  the  bauxite  of  Var  and  Herault  and  gives 
analyses.  In  the  red  mineral  of  Var  druses  occur  with  white  bauxite 
running  as  high  as  85  per  cent  A12C>3,  and  15  per  cent  H2O,  cor- 
responding to  the  formula  A12O3  +  H2O.  He  refers  with  apparent 
approval  to  the  prevailing  theory  of  the  formation  of  bauxite,  accord- 
ing to  which  solutions  of  the  chlorides  of  aluminum  and  iron  in  contact 
with  carbonate  of  lime  undergo  double  decomposition,  forming 
alumina,  iron  oxide,  and  calcium  chloride.  Other  deposits  in  the 
south  of  France,  in  Ireland,  Austria,  and  Italy,  seem  to  him  to  con- 
firm this  view,  because  they  also  rest  upon  or  are  associated  with  lime- 
stone. The  bauxite  deposit  in  Puy  de  Dome  can  not,  however,  be 
explained  by  this  theory,  because  it  is  not  associated  with  limestone, 
but  rests  directly  upon  gneiss  and  is  partly  covered  by  basalt.  The 

1  Mineral  Resources  of  the  United  States,  1891,  p.  148. 

2  Bulletin  de  la  Societe  Geologique  de  France,  XXVIII,  1871,  p.  98. 

3  Bulletin  de  la  Societe  Geologique  de  France,  XVI,  1888,  p.  345. 


OXIDES.  93 

geological  sketch  map  of  the  deposit  near  Madriat,  Puy  de  Dome, 
shows  gneiss,  basalt,  with  uncovered  bauxite  largely  predominating, 
and  patches  of  Miocene  clay,  while  a  geological  section  of  the  deposit 
near  Villeveyrac,  Herault,  shows  the  bed  of  bauxite  conformably 
following  the  flexures  of  the  limestone  formation  when  covered  by 
more  recent  beds,  and  when  exposed  and  denuded  occupying  cavities 
and  pockets  in  the  limestone.  This  occurrence  is  substantially  the 
same  as  that  of  the  neighboring  Baux.  M.  Ange  agrees  with  M. 
Coquand  in  attributing  the  bauxite  to  geyserian  origin,  but  uses  as 
an  illustration  of  the  contemporaneous  formation  of  bauxite  the 
deposits  from  the  geysers  of  the  Yellowstone  Park,  which  is  evidently 
due  to  a  misunderstanding.  No  petrographical  examination  of  the 
bauxite  of  Puy  de  Dome  was  made  nor  any  attempt  to  trace  a 
genetic  relation  between  the  latter  and  the  accompanying  basalt. 
The  occurrence  is,  however,  noteworthy,  and  an  examination  might 
show  that  it  is  another  instance  of  the  direct  derivation  of  bauxite 
from  basalt,  which  is  maintained  somewhat  imperfectly  in  the  two 
following  instances. 

Lang  l  describes  the  bauxite  in  Ober-Hessen,  as  found  in  the 
fields  in  rounded  masses  up  to  the  size  of  a  man's  head,  embedded  in 
a  clay  colored  with  iron  oxide.  The  chemical  composition  and 
petrographical  examination  seems  to  show  that  it  is  a  decomposition 
product  of  basalt.  The  process  he  explains  as  follows :  By  the  weath- 
ering of  the  plagioclase  feldspars,  augite,  and  olivine,  nearly  all  the 
silica  had  been  removed,  together  with  the  greater  part  of  the  lime 
and  magnesia;  the  iron  had  been  oxidized  and  hydrate  of  alumina 
formed.  The  residue  of  the  silica  had  crystallized  as  quartz  in  the 
pores  of  the  mineral. 

A  more  detailed  account  of  the  derivation  of  bauxite  from  basalt 
is  given  in  an  inaugural  dissertation  by  A.  Liebreich.2  The  localities 
described  are  the  southern  slope  of  the  Westerwald  near  Miihlbach, 
Hadamar,  in  the  neighborhood  of  lesser  Steinheim,  near  Hanau,  and 
especially  the  western  slope  of  the  Vogelsberg,  Germany.  Chemical 
analyses  show  certain  differences  in  the  composition  of  samples  from 


1  Berichte  der  Deutschen  Chemischen  Gesellschaft,  XVII,  1884,  p.  2892. 

2  Abstracted  in  the  Chemisches  _  entralblatt,  1892,  p.  94. 


94  THE  NON-METALLIC  MINERALS 

different  places,  the  smaller  amount  of  water  in  the  French  bauxite 
causing  him  to  refer  it  to  diaspore,  while  the  Vogeisberg  mineral  is 
probably  gibbsite  (hydrargillite) .  The  Vogelsberg  Dauxite  occurs  in 
scattered  lumps  or  small  masses,  partly  on  the  surface  and  partly 
embedded  in  a  grayish-white  to  reddish-brown  clay,  which  contains 
masses  of  basaltic  iron  ore  and  fragments  of  more  or  less  weathered 
basalt  itself.  Although  the  latter  was  associated  intimately  with  the 
bauxite,  a  direct  and  close  connection  of  the  two  could  not  be  found, 
but  an  examination  of  thin  sections  of  the  Vogelsberg  bauxite  showed 
that  most  specimens  still  possessed  a  basaltic  (anamesite)  structure, 
which  enabled  the  author  to  determine  the  former  constituents  with 
more  or  less  certainty.  Lath-shaped  portions  representing  altered 
plagioclase  feldspars  filled  with  a  yellowish  substance  preponder- 
ated. Filling  the  spaces  between  these  were  cloudy,  yellow,  brown, 
and  black  transparent  masses  which  had  evidently  taken  the  place 
of  the  former  augite.  Laths  and  plates  of  titanic  iron,  often  fractured, 
were  commonly  present,  and  the  contours  of  altered  olivine  could  be 
clearly  made  out.  The  basalt  of  the  neighborhood  showed  a  structure 
fully  corresponding  with  the  bauxite.  Olivine  and  titanic  iron 
oxide  were  found  in  the  clay  by  washing.  The  basaltic  iron  ore 
also  showed  the  same  structure. 

But  two  localities  in  the  United  States  have  thus  far  yielded  bauxite 
in  commercial  quantities.  These  are  in  Arkansas  and  the  Coosa 
Valley  of  Georgia  and  Alabama. 

According  to  Branner  the  Arkansas  beds  occur  near  the  railway 
in  the  vicinity  of  Little  Rock,  Pulaski  County,  and  near  Benton, 
Saline  County.  The  exposures  vary  in  size  from  one  to  twenty 
or  more  acres,  and  aggregate  something  over  a  square  mile.  This 
does  not,  in  all  probability,  include  the  total  area  covered  by  bauxite 
in  the  counties  mentioned,  for  the  method  of  occurrence  of  the  deposits 
leads  to  the  supposition  that  there  are  others  as  yet  undiscovered. 

Like  all  bauxite,  the  Arkansas  material  varies  more  or  less  in 
color  and  in  chemical  composition.  At  a  few  places  it  is  so  charged 
with  iron  that  attempts  have  been  made  to  mine  it  for  iron  ore. 
Some  of  the  samples  from  these  pits  assay  over  50  per  cent  of  metallic 
iron.  This  ferruginous  kind  is  exceptional,  however.  From  the 
dark-red  varieties  it  grades  through  the  browns  and  yellows  to  pearl- 


OXIDES.  95 

gray,  cream  colored  and  milky  white,  the  pinks,^  browns,  and  grays 
being  the  more  abundant.  Some  of  the  white  varieties  have  the 
chemical  composition  of  kaolin,  while  the  red,  brown,  and  gray  have 
.but  little  silica  and  iron,  and  a  high  percentage  of  alumina.  The 
analyses  given  on  page  91  show  the  composition  of  this  bauxite  as 
compared  with  that  of  other  localities. 

According  to  C.  W.  Hayes  1  the  bauxite  of  the  Bryant  district 
in  Saline  County  is  a  decomposition  product,  in  place,  of  nepheline 
syenite.  The  bauxite  bed  is  described  as  resting  directly  upon  a 
kaolinized  type  of  the  syenite  (locally  known  as  chimney  rock),  and 
overlaid  by  Tertiary  sands  and  gravels.  The  thickness  of  the  bed 
over  a  large  part  of  the  district  is  from  10  to  15  feet,  though  in  places 
reaching  a  maximum  of  40  feet.  Both  the  underlying  kaolinized 
rock  and  the  overlying  Tertiary  sands  and  gravels  are  more  easily 
eroded  than  the  bauxite  and  hence  the  latter,  where  erosion  is  well 
advanced,  is  apt  to  stand  out  in  the  form  of  a  low  ridge.  Two 
distinct  types  of  ore  are  recognized  in  this  district,  (i)  granitic  and 
(2)  pisolitic.  The  first  mentioned  lies  next  to  the  kaolinized  syenite, 
is  of  a  yellowish-gray  color,  a  spongy  structure  and  is  quite  free  from 
any  trace  of  pisolites,  showing,  on  the  contrary,  distinct  traces  of 
of  the  crystalline  ("granitic")  structure  of  the  original  syenite, 
in  which  the  nepheline  and  orthoclase  have  been  preserved  only 
in  form  of  skeletons  of  alumina.  Original  cleavage  surfaces  of  these 
minerals  can  even  at  times  be  detected,  though  more  frequently  the 
structure  is  quite  obliterated.  This  type  of  ore  occurs  also  in  the 
form  of  well-rounded  boulders  from  2  or  3  inches  to  2  feet  in  diameter. 
Such  are  surrounded  by  a  dense  structureless  shell  or  crust  from 
J  to  |  of  an  inch  in  thickness,  but  within  which  the  material  resumes 
the  normal,  spongy  form.  Both  portions  have  essentially  the  same 
composition.  The  boulders  were  presumably  simply  waterworn 
masses  of  the  syenite.  Dr.  Hayes  regards  this  form  of  the  bauxite 
as  in  every  case  derived  directly  from  the  syenite  by  the  decomposi- 
tion of  the  feldspar  and  nepheline  (elaeolite),  and  the  removal  in 
solution  of  the  silica,  lime  and  alkalies.  The  second  class  of  ore 
mentioned — the  pisolitic — forms  the  upper  part  of  the  bauxite  bed, 

1  Twenty-first  Annual  Report,  U.  S.  Geological  Survey,  1899- 1900, Part.  Ill,  p.  446. 


96  THE  NON-METALLIC  MINERALS. 

or  sometimes  constitutes  the  entire  bed,  resting  directly  upon  tha 
kaolin.  There  is  a  well-marked  gradation  in  the  character  of  the 
ore  from  one  part  of  the  district  to  another,  the  one  sometimes  pre- 
vailing and  sometimes  the  other. 

The  origin  of  the  two  types,  as  here  associated,  has  not  been 
satisfactorily  worked  out,  though  possibly  that  of  the  pisolitic  type 
offers  the  fewest  difficulties.  After  a  discussion  of  the  various 
possibilities,  Dr.  Hayes  sums  up  the  matter  as  follows : 

"The  syenite  of  the  bauxite  region  was  intruded  under  a  light 
cover  of  Paleozoic  rocks.  These  were  subjected  to  rapid  erosion 
and  the  surface  of  the  syenite  was  exposed.  Either  its  subjacent 
portions  retained  a  considerable  portion  of  their  original  heat,  or  a 
fresh  supply  of  heat  was  furnished  by  renewed  intrusions  or  dynamic 
disturbances.  The  region  was  then  covered  by  a  body  of  water 
probably  cut  off  from  the  sea,  and  salt,  or  highly  alkaline.  The 
alkaline  waters  by  some  means  gained  access  to  the  heated  portions 
of  the  syenite  and  dissolved  its  minerals.  The  heated  waters  re- 
turned to  the  surface  heavily  charged  with  the  constituents  of  the 
syenite  in  solution.  They  were  still  efficient  solvents,  however,  and 
acted  upon  the  syenite  at  the  surface,  removing  most  of  the  silica, 
along  with  the  lime  and  the  alkalies,  but  leaving  the  alumina  and 
depositing  in  place  of  the  constituents  removed  about  as  much,  or 
more,  alumina  as  the  rock  originally  contained.  Some  of  the  alumina 
brought  to  the  surface  in  solution  was  deposited  by  this  metasomatic 
process,  replacing  a  part  of  the  silica  removed  from  the  syenite,  but 
a  larger  part  was  thrown  down  as  a  gelatinous  precipitate  on  the 
bottom  of  the  water  body  and  somewhat  evenly  distributed  over 
the  undulating  syenite  surface,  at  the  same  time  acquiring  the  piso- 
litic structure  and  becoming  mingled  with  the  boulders  of  aluminized 
syenite.  Most  of  the  spring  exits  were  in  the  immediate  vicinity 
of  the  syenite  areas,  so  that  there  the  water  was  most  strongly 
impregnated  with  the  various  salts  in  solution  and  hence  precipitation 
of  the  alumina  was  most  rapid.  Wherever  the  ascending  solutions 
found  their  way  to  the  surface  by  an  isolated  conduit  through  the 
Tertiary  sediment  already  deposited,  a  local  deposit  of  greater  or 
less  extent  was  formed.  The  precipitation  of  the  alumina  must 
have  taken  place  almost  immediately  after  the  solution  emerged 


OXIDES.  97 

from  the  conduit,  otherwise  the  bauxite  would  have  been  much 
more  widely  disseminated,  or  even  entirely  dissipated  in  the  sur- 
rounding sediments." 

As  stated  above,  and  as  acknowledged  by  Dr.  Hayes,  this  theory 
is  not  altogether  satisfactory,  far  less  so,  in  fact,  than  that  proposed 
for  the  formation  of  the  deposit  in  Georgia  and  Alabama.  The 
chief  difficulty  lies  in  the  finding  of  a  satisfactory  solvent  for  the 
original  aluminous  silicate  and  a  cause  for  the  rapid  precipitation 
of  the  alumina,  when  once  in  solution. 

The  Georgia  and  Alabama  deposits,  according  to  Hayes,  are 
found  irregularly  distributed  within  a  narrow  belt  of  country  extending 
from  Adairsville,  Georgia,  southwestward,  a  distance  of  60  miles, 
to  the  vicinity  of  Jacksonville,  Alabama.  The  only  points  at  which 
it  has  been  worked  on  a  commercial  scale  are  at  Hermitage  furnace, 
5  miles  north  of  Rome,  Georgia,  nsar  Six  Mile  Station,  south  of 
Rome,  and  in  the  dike  district  near  Rock  Run,  Alabama.  (See 
Fig.  21.)  The  oldest  rocks  of  the  region  are  of  Cambrian  Age,  and 
are  subdivided  on  lithologic  grounds  into  two  formations,  the  Rome 
sandstone  below  and  the  Connasauga  shale  above.  The  former 
consists  of  700  to  1,000  feet  of  thin-bedded  purple,  yellow,  and  white 
sandstone  and  sandy  shales.  The  Connasauga  formation  is  between 
2,000  and  3,000  feet  in  thickness.  It  consists  at  the  base  of  fine 
aluminous  shales;  the  upper  portion  is  more  calcareous,  and  locally 
passes  into  heavy  beds  of  blue  seamy  limestone. 

Above  the  shale  is  the  Knox  dolomite.  It  consists  of  from  3,000 
to  4,000  feet  of  gray,  semicrystalline,  siliceous  dolomite.  The  silica 
is  usually  segregated  in  nodules  and  beds  of  chert.  These,  in  the 
process  of  weathering,  remain  upon  the  surface,  and  with  the  other 
insoluble  constituents  form  a  heavy,  residual  mantle  a  hundred  feet 
or  more  in  thickness  covering  all  the  outcrops  of  the  formation.  It  is 
associated  with  these  residual  materials  that  the  extensive  deposits 
of  limonite  and  bauxite  are  found.  The  geological  structure  of  the 
region  is  complicated,  and  for  its  details  the  present  reader  is  referred 
to  Dr.  Hayes's  original  paper. 

The  bauxite  deposits  in  the  Rock  Run  district  are  regarded  as 
typical  for  the  entire  region,  and  are  described  as  follows : 

Four  bodies  of  the  ore  were  being  worked  in  1893  on  a  con~ 


98 


THE  NON-METALLIC  MINERALS. 


siderable  scale,  and  all  show  practically  the  same  form.  The  south- 
ernmost of  the  four,  called  the  Taylor  bank,  is  located  3  J  miles  north- 
east of  Rock  Run,  near  the  western  base  of  Indian  Mountain.  (See 
Fig.  21).  Although  the  heavy  mantle  of  residual  material  effectually 
conceals  the  underlying  rocks,  the  ore  appears  to  be  exactly  upon  the 


MAP  SHOWING  THE 

GEOLOGICAL  RELATIONS 

Of  THE 

GEORGIA  AND  ALABAMA  BAUXITE  DEPOSITS 


I      CC   [CONNA8AUOA       \rjSrfA  ROCKWOOQ 

MAJOR  THRUST  FAULTS  MINOR  THRUST  FAULTS 


FIG.  21. 
[After  C.  W.  Hayes,  U.  S.  Geological  Survey.] 

faulted  contact  between  the  narrow  belt  of  Knox  dolomite  on  the 
northwest  and  the  sandy  shales  and  quartzites  of  Indian  Mountain 
on  the  southeast.  It  is  covered  by  three  or  four  feet  of  red  sandy 
clay,  in  which  numerous  fragments  of  quartzite  are  embedded.  The 
ore-body  is  an  irregularly  oval  mass,  about  40  by  80  feet  in  size.  Its 
contact  with  the  surrounding  residual  clay,  wherever  it  could  be 
observed,  appears  to  be  sharp  and  distinct,  and,  about  the  greater 


OXIDES.  99 

portion  of  its  circumference,  very  nearly  vertical.  A  certain  amount 
of  bedding  is  observable,  although  no  trace  can  be  detected  in  the 
surrounding  residual  material.  Upon  the  northwestern  or  down- 
hill side  of  the  ore-body  this  bedding  is  very  distinct.  Layers  of 
differently  colored  and  differently  textured  ore  alternate  in  regular 
beds,  a  few  inches  in  thickness,  and  above  these  are  thinner  beds 
of  chocolate  and  red  material,  probably  containing  considerable 
kaolin.  These  beds  have  a  steep  dip,  somewhat  greater  than  the 
slope  of  the  hillside,  but  in  the  same  direction.  They  are  not  simply 
inclined  planes,  however,  but  are  curved,  so  as  to  form  a  steeply 
pitching  trough.  With  increasing  distance  from  the  ore-body  the 
lamination  becomes  less  distinct,  and  the  beds  pass  gradually  into 


FIG.  22. — Section  showing  the  relation  of  bauxite  to  mantle  of  residual  clay  in  Georgia. 
[After  C.  W.  Hayes,  U.  S.  Geological  Survey.] 

a  homogeneous  mottled  clay.  The  accompanying  section,  Fig.  22, 
shows  these  relations  of  the  ore  and  residual  mantle. 

At  the  Dyke  bank  (see  Fig.  21),  about  a  mile  northeast  of  the  one 
above  described,  the  stratification  is  well  shown  in  portions  of  the 
deposit.  Beds  of  yellow  and  gray,  fine-grained  material  alternate 
with  others  of  pisolitic  ore.  The  beds  dip  at  an  angle  of  about  40,° 
and  are  curved  so  as  to  form  a  steep  trough.  The  compact  material 
also  shows  distinct  cross-bedding,  both  primary  and  secondary  planes 
dipping  in  the  same  direction. 

In  the  Gain's  Hill  bank,  about  250  yards  north  of  the  Dyke  bank, 
the  ore-body  shows  a  more  regularly  oval  form  than  in  most  of  the 
other  deposits,  and  is  also  somewhat  dome-shaped,  swelling  out 
laterally  from  the  surface  downward,  as  far  as  the  working  has  pro- 
gressed. 

Although  some  of  the  workings  have  gone  to  a  considerable  depth 
(in  a  few  cases  50  feet  or  more),  the  bottom  of  the  ore-body  has 


loo  THE  NON-METALLIC  MINERALS. 

not  been  reached  in  any  case.  The  ore  varies  in  composition  with 
depth,  but  not  in  a  uniform  manner,  nor  more  than  do  different 
portions  at  the  same  depth.  The  deepest  pits  have  not  gone  below 
the  base  of  the  surrounding  residual  mantle,  so  that  no  observations 
have  yet  been  made  with  regard  to  the  relations  between  the  ore 
and  the  country  rock;  and  nothing  has  yet  been  observed  which 
warrants  the  conclusion  that  the  ore,  if  followed  to  sufficient  depth, 
will  be  found  interbedded  with  the  underlying  formations,  or  even 
that  it  will  be  found  occupying  cavities  in  the  limestone — although 
the  latter  is  quite  possible. 

Concerning  the  origin  of  these  deposits  it  is  stated  that  no  eruptive 
rocks,  either  ancient  or  modern,  are  found  in  the  vicinity,  nor  are  there 
any  rocks  in  this  region  which,  by  weathering,  could  yield  bauxite  as 
a  residual  product.  Hence,  any  satisfactory  explanation  must  give 
the  source  from  which  the  material  was  derived,  the  means  by  which 
it  was  transported,  and  the  process  of  its  local  accumulation. 

The  ore  is  associated  with  the  Knox  dolomite  or  with  calcareous 
sandy  shales  immediately  overlying  the  dolomite.  The  Connasauga 
formation,  consist'ng  of  2,000  feet  or  more  of  aluminous  shales, 
invariably  underlies  the  dolomite  at  greater  or  less  distance  beneath 
the  ore-bearing  regions,  and  is  probably  the  source  from  which  the 
alumina  was  derived. 

The  region  has  been  profoundly  faulted.  Undoubtedly  the 
dislocations  of  the  strata  generated  a  large  amount  of  heat.  The 
fractures  facilitated  the  circulation  of  water,  and  for  considerable 
periods  the  region  was  probably  the  seat  of  many  thermal  springs 
which  it  is  reasonable  to  suppose  were  the  agents  by  which  the 
alumina  salt  was  brought  to  the  surface. 

The  oxygen  contained  in  the  meteoric  waters  percolating  at  great 
depths  through  the  fractured  strata  would  readily  oxidize  the  sul- 
phides disseminated  in  the  aluminous  shales.  Sulphates  would  thus 
be  formed,  the  most  abundant  of  which  was  ferrous  sulphate.  Some 
sulphate  of  aluminum  must  also  have  been  formed,  together  with  the 
double  sulphate  of  potassium  and  aluminum,  especially  in  the  absence 
of  sufficient  potash  to  form  alum  with  the  whole. 

In  its  passage  from  the  underlying  shales  through  several  thou- 
sand feet  of  dolomite  the  heated  water  would  become  highly  charged 


OXIDES.  101 

with  lime,  in  addition  to  the  ferrous  and  aluminous  salts  already  in 
solution.  But  calcium  carbonate  reacts  upon  aluminum  sulphate, 
forming  a  gelatinous  or  flocculent  precipitate  which  consists  of  alu- 
minum hydroxide  and  the  basic  sulphate.  This  reaction  may  have 
taken  place  at  great  depth  and  the  resulting  flocculent  precipitate 
been  brought  to  the  surface  in  suspension.  From  analogy  with 
pisolitic  sinter  and  travertine  now  forming,  such  conditions  would 
appear  to  be  highly  favorable  for  the  production  of  the  structures 
actually  found  in  the  bauxite.  The  precipitate  was  apparently 
collected  in  globular  masses  by  the  motion  of  the  ascending  water, 
and  constant  changes  in  position  permitted  these  to  be  coated  with 
successive  layers  of  more  compact  material.  Finally,  after  having 
received  many  such  coatings,  the  pisolites  were  deposited  on  the  bor- 
ders of  the  basin,  and  the  interstices  filled  by  minute  oolites  formed 
in  a  similar  manner  or  by  the  flocculent  precipitate  itself.  Slight 
differences  in  the  conditions  prevailing  in  the  several  springs,  such  as 
concentration  and  relative  proportion  of  the  various  salts  in  solution, 
also  temperature  and  flow  of  the  water,  would  produce  the  variation 
in  the  character  of  the  ore  observed  at  different  points. 

A  small  portion  of  the  ferrous  sulphate  was  oxidized  and  pre- 
cipitated along  with  the  bauxite,  but  the  greater  part  was  carried 
some  distance  from  the  springs  and  slowly  oxidized,  forming  the 
widespread  deposits  of  limonite  in  this  region. 

Pittman  describes  highly  ferriferous  bauxite  covering  several 
square  miles  of  territory  in  the  Innverell  and  Emmaville  districts 
of  New  South  Wales.  The  material  occurs  "capping  small  hills,  and 
in  many  cases  surrounding  points  of  eruption." 

"It  is  clearly,"  he  says,  "of  volcanic  origin,  and  while  in  some 
cases  it  appears  to  consist  of  volcanic  ash,  in  others  in  may  have  been 
derived  from  the  decomposition  of  basalt  in  situ"  The  analyses 
quoted  show  it  to  run  from  30  to  60  per  cent  of  alumina;  2  to  42 
per  cent  of  iron  oxide;  6  to  32  per  cent  of  water,  and  equally  varying 
proportions  of  silica  and  minor  impurities.1 

Uses. — The  better-known  use  of  bauxite  is  as  an  ore  of  alumi- 
num, for  which  purpose  it  lies  beyond  the  scope  of  the  present  work. 

1  Mineral  Resources  of  N.  S.  Wales,  by  E.  F.  Pittman,  1901. 


102  'THE 'NON-METALLIC  MINERALS. 

It  may,  however,  be  well  to  state  that  before  the  aluminum  can  be 
satisfactorily  extracted  the  ore  is  purified  by  chemical  processes. 
The  principal  use  aside  from  this  is  for  the  manufacture  of  alums 
and  other  aluminum  salts  such  as  are  used  in  baking  powders  and 
dyes.  It  is  believed  that  the  mineral,  owing  to  its  highly  refractive 
qualities,  will  be  utilized  in  the  manufacture  of  fire-brick  and  cru- 
cibles. An  alumino-ferric  cake,  a  by-product  obtained  in  the  puri- 
fying process,  is  claimed  as  of  value  for  sanitary  and  deodorizing 
purposes.  The  price  of  the  crude  ore  varies  greatly,  according  to 
purity.  The  average  price  for  the  past  few  years  has  been  about 
$5  a  ton. 

BIBLIOGRAPHY  OF  CRYOLITE  AND  BAUXITE. 

PAUL  QUALE.     Account  of  the  Cryolite  of  Greenland. 

Annual  Report  of  the  Smithsonian  Institution,  1866,  p.  398. 

M.  H.  COQUAND.     Sur  les  Bauxites  de  la  chaine  des  Alpines  (Bouches-du-Rhone)  et 
leur  age  geologique. 

Bulletin  de  la  Societe  Geologique  de  France,  2d  Ser.,  XXVIII,  1870-71,  pp. 
98-115. 
EDWARD  NICHOLS.     An  Aluminum  Ore. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XVI,  1887,  p.  905. 
P.  JOHNSTRUP.     Sur  le  Gisement  de  la  Kryolithe  au  Greenland. 

Bulletin  de  la  Societe  Mineralogie  de  France,  II,  1888,  p.  167. 
M.  AUGE.     Note  sur  la  Bauxite,  son  origine,  son  age  et  son  importance  geologique. 

Bulletin  de  la  Societe  Geologique  de  France,  3d  Ser.,  XVI,  1888,  p.  345. 
STANISLAS  MEUNIER.     Response  a  des  observations  de  M.  Auge  et  de  M.  A.  de  Gros- 
souvre  sur  1'histoire  de  la  Bauxite  et  des  Minerals  Siderolithiques. 

Bulletin  de  la  Societe  Geologique  de  France,  3d  Ser.,  XVII,  1889,  p.  64. 
R.  L.  PACKARD.     Aluminum. 

Mineral  Resources  of  the  United  States,  1891,  p.  147. 

This  paper  contains  numerous  references  to  which  the  present  compiler  has 
not  had  access. 
HENRY  MCCALLEY.     Bauxite. 

The  Mineral  Industry,  II,  1893,  p.  57. 

C.  WILLARD  HAYES.     The  Geological  Relations  of  the  Southern  Appalachian  Bauxite 
Deposits. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXIV,  1894,  p.  243. 
W.  P.  BLAKE.     Alunogen  and  Bauxite  of  New  Mexico. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXIV,  1894,  p. 

571- 
FRANCIS  LAUR.     The  Bauxites.     A  Study  of  a  New  Mineralogical  Family. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXIV,   1894, 
P-  234. 


OXIDES.  103 

FRANCIS  LAUR.     On  Bauxite. 

Minutes  of  the  Proceedings  of  the  Institute  Civil  Engineers,  CXX,  1894-95, 
Pt.  2,  p.  442. 
J.  C.  BRANNER.     The  Bauxite  Deposits  of  Arkansas. 

The  Journal  of  Geology,  V,  1897,  pp.  263-289. 

THOS.  WATSON.     The  Georgia  Bauxite  Deposits;    their  Chemical  Constitution  and 
Genesis. 

American  Geologist,  July,  1901,  pp.  25-45. 

4.    DIASPORE. 

This  is  a  hydrous  oxide  of  aluminum  corresponding  to  the  for- 
mula A12O3,H2O,  =  alumina,  85  per  cent;  water,  15  per  cent;  hard- 
ness, 6.5  to  7.  It  is  a  whitish,  grayish  sometimes  brownish  or 
yellowish  mineral,  occurring  in  the  form  of  thin  flattened  or  acicular 
crystals  and  also  foliated,  massive,  and  in  thin  plates  or  rarely  stalac- 
titic.  It  h  transparent  to  subtranslucent,  and  sometimes  shows 
violet-blue  colors  when  looked  at  in  one  direction,  or  reddish-blue 
or  asparagus-green  in  others.  Luster,  vitreous  or  pearly. 

Occurrence. — The  mineral  commonly  occurs  with  corundum  and 
emery  in  dolomite  and  granular  limestone  or  crystalline  schists.  In 
the  United  States  it  occurs  in  large  plates  in  connection  with  the 
emery  rock  at  Chester,  Massachusetts. 

Uses. — See  under  Gibbsite. 

5.  GIBBSITE;  HYDRARGILLITE. 

This  is  also,  like  diaspore,  a  hydrous  oxide  of  aluminum,  corre- 
sponding to  the  formula  A1/)3,3H2O,  =  alumina,  65.4  per  cent;  water, 
34.6  per  cent.  The  mineral  is  of  a  whitish,  grayish,  or  greenish 
color,  sometimes  reddish  through  impurities,  and  occurs  in  flattened, 
hexagonal  crystals,  or  in  stalactitic  and  mammillary  and  incrusting 
surfaces.  Its  occurrence  is  similar  to  that  of  diaspore. 

It  has  been  shown  that  the  so-called  laterite  of  the  Seyschellian 
Islands  in  the  Indian  Ocean  is  a  mixture  of  quartz,  iron  oxides  and 
hydrargyllite.  Whether  or  not  the  last  named  is  in  such  form  as 
to  be  of  economic  value  is  not  yet  apparent. 

Uses. — Neither  diaspore  nor  gibbsite  have  as  yet  been  found 
in  sufficient  quantities  to  be  of  economic  importance.  Should 
they  be  so  found,  their  value  as  a  source  of  alumina  is  easily 
apparent. 


104 


THE  NON-METALLIC  MINERALS. 


6.   OCHER. 

The  term  ocher  as  commonly  used  applies  to  earthy  and  pulveru- 
lent forms  of  the  minerals  hematite  and  limonite,  but  which  are  al- 
most invariably  more  or  less  impure  through  the  presence  of  other 
metallic  oxides  and  argillaceous  matter.  In  nature  the  material 
rarely  occurs  in  a  suitable  condition  for  immediate  use,  but  needs 
first  to  be  prepared  by  washing  and  grinding,  and  perhaps  roasting. 

Various  varietal  names  are  applied  to  the  ochers,  according  to 
their  natural  colors  or  sources.  The  original  "  Indian  red  "  was  a 
red  argillaceous  ocher,  with  a  purplish  tinge,  found  on  the  island 
of  Ormuz,  in  the  Persian  Gulf.  A  large  part  of  the  pigment  of  this 
name  is  now  prepared  artificially  from  iron  pyrites.  Umber  is  a  gray, 
brown,  or  reddish  variety  containing  manganese  oxides  and  clay. 
It  derives  its  name  from  Umbria,  in  Italy,  where  material  of  this 
nature  was  first  utilized.  Sienna  is  a  highly  argillaceous  variety,  also 
from  Italy,  near  Sienna. 

The  natural  colors  of  the  ochers  are  dependent  on  the  degree  of 
hydration  and  oxidation  of  material  and  the  kind  and  amount  of 
impurities.  In  a  general  way  the  hematites  are  of  a  deep  red  color, 
while  the  limonites  are  yellow  or  brown.  Either  color  is  liable  to 
shade  variations,  according  to  amount  and  kind  of  impurities.  The 
colors  are  intensified,  or  otherwise  varied,  by  roasting. 

Artificial  ochers  are  produced  by  roasting  iron  pyrites  (sulphide 
of  iron)  or  an  artificial  sulphate  (green  vitriol).  (See  under  Py rite.) 
The  materials  known  commercially  as  rouge,  crocus,  and  Indian  red 
are  quite  pure  ferric  oxide,  prepared  by  roasting  pyrite  or  by  other 
artificial  means. 

COMPOSITION   OF   OCHERS   IN   THEIR  NATURAL   CONDITION. 


Natural  Color.                         Locality. 

Fe203. 

A1203. 

SiO2. 

H20. 

Alks. 

Yellow  .  .  Marksv'lle  Page  Co  Virginia 

33-o 
J  Insol. 

0.5 

1       7-2 

J  

Yellow-brown..  .  .Hancock,  Berks  Co.,  Pennsylvania. 
Deep  brown  Anne  Arundel  Co.  ,  Maryland  
Deep  red-brown.  .Northampton  Co.,  Pennsylvania.  .  . 
Gray  Northampton  Co.,  Pennsylvania.  .  . 
Dark  brown.'  ....  Brandon,  Vermont  

a  36.67 
19.67 
£42.  45 

C  12  .  2O 

dsz.  92 

So 
76 
30 
74 
32 
60 

.00 

•  57 
•  58 

.  10 

.88 

1  0.60 
2.60 
11.85 
5-23 
14.  62 

;  '.'. 

Light  yellow.  .  .  Cartersville  Georgia  

b  55.84 

a.  A  part  of  the  iron  in  a  ferrous  condition,     c.  Iron  exists  mainly  in  a  ferrous  condition. 

b.  Contains  also  some  manganese.  d.  Contains  much  manganese. 


OXIDES. 


COMPOSITION   OF   MANUFACTURED    MINERAL    PAINTS. 


Variety. 

Fe203. 

A1203. 

Si02. 

H2O. 

P203,  MnO, 
CaO. 

Lowe's  metallic  paint  a  
Rossie  red  paint  b.  .  .  . 

78.87 
60.  <o 

3-29 
•?  6? 

11.96 
18  oo 

5-07 

o  33 

0.80 
(    CaCo3 

Light  brown  paint  c.  .   . 

77.26 

7   oo 

ii  84. 

o  06 

1     15.66 

i  84. 

Brown-purple  paint  d  

93-68 

3.06 

T..2O 

(  S.     and 
4      loss. 

(      0.06 

[  

a.  Made  from  red  fossiliferous  ores  mined  at  Atalla,  Alabama,  and  Ooltewah,  Tennessee. 

b.  Made  by  Iron  Clad  Paint  Company,  of  Cleveland,  Ohio,  from  ore  mined  in  Wayne  County, 
New  York. 

c.  From  ore  mined  at  Lake  Superior,  Michigan. 

d.  Ore  from  Jackson  Mine,  Michigan. 

A  "blue  ocher,"  formed  by  the  decomposition  of  the  Utica  shales 
in  Lehigh  County,  Pennsylvania,  has  the  following  composition: 


Constituents. 

Per  Cent. 

Ignition  (water  and  carbon) 

9IO 

Ouartz 

A  A       CQ 

Combined  silica 

26    2£ 

Alumina  with  traces  of  ferric  oxide  
Magnesia 

J7-95 

O    O4. 

Alkalies  etc 

I    26 

100.00 

A  second  variety,  from  ij  miles  northwest  of  Breinigsville,  and 
which  was  sold  as  a  yellow  ocher,  yielded: 

Silica,  60.53;  alumina,  17.40;  ferric  oxide,  9.27;  lime,  0.08; 
magnesia,  1.92;  water,  5.51;  alkalies,  5.27. 

Origin  and,  mode  of  occurrence. — These  vary  greatly.  In  some 
cases  deposits  of  this  nature  are  formed  by  springs.  Such  result 
from  the  leaching  out  from  the  rocks,  by  carbonated  waters,  of  iron 
in  the  protoxide  condition,  and  its  subsequent  deposition  as  a  hy- 
drated  sesquioxide.  In  other  cases  they  are  residual  products 
formed  by  the  removal,  by  solution,  of  the  lime  carbonates  of  cal- 
careous rocks,  leaving  their  insoluble  residues — the  clay  and  iron 
oxides — in  the  form  of  a  red,  yellow,  or  brown  ocherous  clay.  Again, 


106  THE    NON-METALLIC  MINERALS. 

they  may  result  from  the  decomposition  (oxidation)  of  beds  of  pyrite 
(iron  disulphide)  and  from  the  decomposition  of  beds  of  hematite, 
and  by  the  disintegration  of  the  more  compact  forms  of  limonite. 
Still  again,  they  may  result  from  the  decomposition  of  schists  and 
other  rocks  rich  in  iron-bearing  silicate  minerals.  The  yellow  ochers 
of  the  Little  Catoctin  Mountains,  near  Leesburg,  Virginia,  are  thus 
stated  to  be  residual  products  from  the  decomposition  of  hydro- 
mica  or  damourite  schists. 

An  extensive  deposit,  or  line  of  deposits,  of  yellow  ocher  near 
Cartersville,  Georgia,  is  described  as  occurring  in  the  form  of  ex- 
tremely irregularly  branching  veins  intersecting  a  shattered  quartzite 
of  Cambrian  age.  The  veins  often  expand  into  bodies  of  consider- 
able size,  and  when  the  ocher  is  removed,  rooms  6  to  10  feet  in 
diameter  are  sometimes  left,  connected  by  narrow,  winding  passages. 
The  contact  between  the  ocher  and  quartzite  is  never  sharp,  but 
there  is  a  gradual  transition  from  one  to  the  other.  "  The  quartzite 
first  becomes  stained  a  light  yellow  and  loses  its  compact,  close- 
grained  texture.  This  phase  passes  into  a  second,  in  which  the  rock 
is  perceptibly  porous,  having  a  rough  fracture  and  a  harsh  feel,  and 
containing  enough  ocher  to  soil  the  fingers.  In  the  next  phase  the 
ocher  preponderates,  but  is  held  together  by  a  more  or  less  con- 
tinuous skeleton  of  silica,  although  it  can  be  readily  removed  with  a 
pick.  The  final  stage  in  the  transition  is  the  soft  yellow  ocher, 
filling  the  veins,  which  crumbles  on  drying,  and  contains  only  a  small 
proportion  of  silica  in  the  form  of  sand  grains."  An  examination  with 
the  microscope  seems  to  point  unmistakably  to  an  origin  through 
a  chemical  replacement  of  the  silica  of  the  quartzite  -by  the  iron 
oxide,  as  has  been  shown  by  Van  Hise  to  have  taken  place  in  the 
case  of  the  hematite  ores  of  the  Lake  Superior  region.  The  chem- 
istry of  the  process  is  not,  however,  quite  clear.  The  rocks  are 
faulted,  and  may  at  some  time  have  been  permeated  by  heated 
solutions.  Water  from  the  surface  rocks  containing  in  solution  iron 
carbonate  or  other  ferrous  salt,  penetrating  downward  through  the 
shattered  quartzite,  would  meet  with  oxidizing  solutions,  and  the  iron 
would  be  precipitated  as  limonite,  and  in  this  particular  case  in  an 
ocherous  form.  Thus  far  the  reaction  is  not  difficult  to  understand, 


OXIDES.  107 

but  to  account  for  the  removal  of  the  silica  is  not  so  easy.  The 
heated  solutions  from  below,  perhaps  alkaline,  may  have  been  instru- 
mental in  bringing  it  about,  and  perhaps  also  the  carbonic  acid 
liberated  during  the  process  of  oxidation.1 

A  paint  ore  found  near  Lehigh  Gap,  Carbon  County,  Pennsylva- 
nia, though  not  properly  an  ocher,  may  be  described  here  for  want  of 
a  better  place.  The  raw  material  is  a  dull  shaly  or  slaty  rock, 
of  a  dark  gray  color,  sandy  texture,  and  quite  hard,  and.  if  descrip- 
tions ara  correct  is  probably  an  arenaceous  siderite  or  carbonate 
of  iron. 

According  to  C.  E.  Hesse  2  the  paint  bed  is  of  unknown  extent 
except  so  far  as  indicated  by  outcrops  along  the  southern  border 
of  Carbon  County,  about  27  miles  north  of  Bethlehem,  where  it 
occurs  in  a  well-defined  ridge  of  Oriskany  sandstone.  Along  the 
outcrop  the  beds  are  covered  by  a  cap  of  clay  and  by  the  decomposed 
portion  of  the  Marcellus  slate.  Beginning  with  this  slate  the  meas- 
ures occur  in  the  following  descending  order: 

a.  Hydraulic  cement   (probably  Upper  Helderberg),  very  hard 
and  compact. 

b.  Blue  clay,  about  6  inches  thick. 

c.  Paint  ore,  varying  from  6  inches  to  6  feet  in  thickness. 

d.  Yellow  clay,  6  feet  thick. 

e.  Oriskany  sandstone,  forming  the  crest  and  southern  side  of 
the  ridge.     It  is  extremely  friable,  and  disintegrates  so  readily  that 
it  is  worked  for  sand  at  many  points.     (See  Fig.  23.) 

The  paint  bed  is  not  continuous  throughout  its  extent.  It  is 
faulted  at  several  places;  sometimes  it  is  pinched  out  to  a  few  inches, 
and  again  increases  in  width  to  6  feet.  The  ore  is  bluish  gray, 
resembling  limestone,  and  is  very  hard  and  compact.  The  bed  is 
of  a  lighter  tint,  however,  in  the  upper  than  in  the  lower  part, 
and  this  is  probably  due  to  its  containing  more  hydraulic  cement 


1  Hayes  and  Eckel,  Contributions  to  Economic  Geology,  Bulletin  No.  213,  Series 
A,  Economic  Geology,  XXIV,  U.  S.  Geological  Survey,  1902,  pp.  427-432.     See  also 
Bulletin  No.  13,  Geological  Survey  of  Georgia,  1906. 

2  Transactions  of  the  American  Institute  of  Mining  Engineers,  XIX,  1891,  p.  321. 


io8 


THE  NON-METALLIC  MINERALS. 


in  the  upper  strata.     The  paint  ore  contains  partings  of  clay  and 
slate  at  various   places.     At  the  Rutherford  shaft  there  are  five 

bands  of  ore  alternating 
with  clay  and  slate,  as 
follows :  Sandstone  (hang- 
ing wall),  clay,  ore,  slate, 
ore,  clay,  ore,  slate,  ore, 
cement,  slate  (foot  wall). 
These  partings,  however, 
are  not  continuous,  but 
pinch  out,  leaving  the  ore 
without  the  admixture  of 
clay  and  slate.  Near  the 
outcrop  the  bed  becomes 
brown  hematite,  due  to  the 
leaching  out  of  the  lime 
and  to  complete  oxidation. 
Occasionally  streaks  of  hem- 
atite are  interleaved  with 
the  paint  ore.  In  driving 
up  the  breasts  toward  the 
outcrop  the  ore  is  found  at 
the  top  in  rounded,  partially 
FIG.  23.— Section  across  the  bed,  Rutherford  and  oxidized,  and  weathered 

Barclay  Mine.  „    -        .,.         . 

[After  C.E.  Hesse.]  masses>       called          bomb- 

shells,"    covered  with   iron 

oxide  and  surrounded  by  a  bluish  clay.     In  large  pieces  the  ore 
shows  a  decided  cleavage. 

Some  of  the  mines  of  Clinton  iron  ore  (hematite)  in  New  York 
State,  and  the  hematite  ores  of  St.  Lawrence  County,  are  used  in 
paint  manufacture,  as  are  also  ferruginous  shales  and  slates.  The 
green,  brown  and  blue  shales  occurring  in  the  Chemung  formation 
in  Cattaraugus  County  have  thus  been  utilized  as  well  as  the  red 
shale  occurring  at  the  base  of  the  Salina  formation  in  Herkimer 
County.  The  utility  of  the  material  depends,  naturally,  upon  the 
amount  of  iron  contained  by  it  and  the  facility  with  which  it  can 
be  reduced  to  a  gritless  powder.  Even  the  red  roofing  slates 


OXIDES.  109 

of  Washington  County  find  a  limited  application  along  these 
lines. 

A  mineral  paint  mined  on  Porter  Creek,  near  Healdsburg, 
Sonoma  County,  California,  is  said  1  to  consist  of  hematite  and 
silicate  of  iron  in  the  form  of  a  compact  mass  lying  between  horn- 
blendic  rock,  actinolite,  and  mica  schist  on  the  one  side  and  rotten 
serpentine  t>n  the  other.  The  vein  has  a  north-of-east  course,  and 
is  some  60  feet  in  width.  The  material  is  mined  from  a  tunnel, 
crushed,  ground  between  buhrstones,  and  bolted,  making  a  paint 
fit  for  mixing  with  oils  or  japan. 

Preparation. — As  already  intimated,  only  a  small  portion  of  the 
ocher  is  used  in  its  natural  condition,  it  being  first  roasted  and  then 
ground,  the  grinding  being  either  "dry"  or  in  oil.  The  roasting 
deepens  the  color  to  a  degree  dependent  upon  the  length  of  time  the 
ore  is  exposed.  Yellows  are  converted  into  browns  and  reds,  and 
the  ocher  rendered  less  hydrous  at  the  same  time.  The  crude  ore 
as  mined  is  not  infrequently  separated  from  the  coarser  or  heavier 
impurities  by  a  process  of  washing  in  running  water,  whereby  the 
ocher,  in  a  state  of  suspension,  is  drawn  off  into  vats,  where  it  is 
allowed  to  settle,  the  water  decanted,  and  the  sediment  made  up 
into  bricks  and  dried,  when  it  is  ready  for  grinding. 

The  method  pursued  at  Caldbeck  Falls,  in  Cumberland,  Eng- 
land, is  as  follows,  the  ocher  occurring  here  in  a  vein  in  granite  and 
admixed  with  quartz : 2 

"The  umber  is  brought  down  by  an  overhead  tramway  and 
passed  through  a  hopper  into  a  wash  barrel  consisting  of  a  cylinder 
formed  of  parallel  bars  one-eighth  of  an  inch  apart,  having  a  perfo- 
rated pipe  conveying  water,  for  its  axis.  By  this  means  the  umber 
is  washed  through,  the  quartz  being  retained ;  the  former  then  passes 
to  an  edge- runner,  the  casing  of  which  is  of  sufficient  depth  to  allow 
of  the  submersion  of  the  rollers.  The  rate  of  revolution  is  about 
14  to  the  minute,  and  the  finer  floating  particles  flow  into  the  drag 
mill.  The  bed  of  this  mill  is  a  single  block  of  granite,  and  over  it 

1  Twelfth  Annual  Report  of  the  State  Mineralogist,  1894,  p.  406. 

2  Journal  of  the  Society  of  Chemical  Industry,  October,  1890,  p.  953. 


no 


THE  NON-METALLIC  MINERALS. 


the  four  buhrstone  blocks  are  dragged ;  the  finer  ( floating '  particles 
of  umber  pass  to  a  second  mill  of  the  same  kind,  then  through  a 
brass  wire  sieve  (to  remove  particles  of  peat  and  heather  that  have 
been  floating  throughout  the  process)  to  settling  tanks,  composed  of 
brickwork  lined  with  cement.  After  settling  for  four  hours  four- 
fifths  of  the  water  is  drawn  off,  and  the  umber,  now  of  the  con- 
sistency of  slurry,  filter-pressed  and  dried.  It  has  the  following 
composition : 


Constituents. 

Per  Cent. 

Ferric  oxide 

4-7    14 

Manganese  dioxide  

II    17 

Cupric  oxide  

3     2T. 

Alumina  

7.66 

Lime 

Trace 

IVlagnesia 

Trace 

Silica 

24.  70 

Combined  water     

6  18 

100.08 

In  this  form  it  is  put  upon  the  market. 

At  the  Lehigh  Gap  Mines  the  ore,  as  it  comes  from  the  mines, 
is  free  from  refuse,  great  care  having  been  taken  to  separate  slate 
and  clay  from  it  in  the  working  places.  It  is  hauled  in  wagons  to 
kilns,  which  are  situated  on  a  hillside  for  convenience  in  charging. 
The  platform  upon  which  the  ore  is  dumped  is  built  from  the  top  of 
the  kiln  to  the  side  of  the  hill.  The  ore  is  first  spalled  to  fist  size 
and  freed  from  slate,  and  is  then  carried  in  buggies  to  the  charging 
hole  of  the  kiln. 

The  kiln  works  continuously,  calcined  ore  being  withdrawn  and 
fresh  charges  made  without  interruption.  The  ore  is  subjected  for 
forty-eight  hours  to  the  heat,  which  expels  the  moisture,  sulphur, 
and  carbon  dioxide.  About  ij  tons  of  calcined  ore  are  withdrawn 
every  three  hours  during  the  day.  The  outside  of  the  lumps  of 
calcined  ore  has  a  light-brown  color,  while  the  interior  shows  upon 
fracture  a  darker  brown.  Great  care  is  necessary  to  regulate  the 
heat  so  that  the  ore  is  not  overburnt.  When  this  happens  the 


OXIDES.  in 

product  has  a  black,  scoriaceous  appearance,  and  is  unfit  for 
the  manufacture  of  metallic  paint,  as  it  is  extremely  hard  to 
grind. 

The  calcined  ore  is  carried  from  the  kiln  in  wagons  to  the  mill, 
where  it  is  broken  to  the  size  of  grains  of  corn  in  a  rotating  crusher. 
The  broken  ore  is  carried  by  elevators  to  the  stock  bins  at  the  top 
of  the  building,  and  thence  by  shutes  to  the  hopper  of  the  mills,  which 
grind  it  to  the  necessary  degree  of  fineness.  Elevators  again  carry 
it  to  the  packing  machine  by  a  spout,  and  it  is  packed  into  barrels 
holding  500,  300,  or  100  pounds  each. 

Uses. — The  ochers  are  among  the  most  widespread  and  readily 
accessible  of  coloring  materials,  and  have  been  used  by  savage  and 
civilized  people,  both  ancient  and  modern.  The  war  paint  of  the 
American  Indian  was  not  infrequently  an  ocher  mixed  with  oil  or 
grease.  According  to  William  J.  Russell,1  the  pigments  used  by  the 
Egyptians  and  others  since  the  earliest  times  were  of  hematite,  and 
mostly  of  an  oolitic  variety,  apparently  closely  corresponding  to 
the  Clinton  hematites  of  New  York  State.  As  tested,  such  were 
found  to  contain  from  79.11  to  81.34  per  cent  ferric  oxide. 

The  ochers  are  now  used  mainly  in  the  manufacture  of  paints  for 
exteriors,  as  of  buildings,  the  rolling  stock  of  railways,  bridges,  and 
metal  roofing.  They  are  also  used  as  a  pigment  for  coloring  mor- 
tars, and  in  the  manufacture  of  linoleums  and  oilcloths.  Mixed 
with  a  certain  proportion  of  oxide  of  manganese,  the  ochers  have 
been  used  to  produce  desirable  colors  in  earthenware.  The  Cald- 
beck  Falls  material  noted  is  said  to  be  utilized,  in  addition  to  the  pur- 
poses mentioned,  for  the  coloring  of  various  kinds  of  brown  paper. 

The  raw  ocher  (that  is,  ocher  not  roasted),  of  a  light-yellow  color, 
was  at  one  time  in  great  demand,  particularly  throughout  New 
England,  for  painting  floors. 

The  value  of  the  prepared  material  is  but  a  few  cents  a  pound. 

1  Nature,  XLIX,  1894,  p.  374- 


H2  THE  NON-METALLIC  MINERALS. 

BIBLIOGRAPHY. 

FRANK  A.  HILL.     Report  on  the  Metallic  Paint  Ores  along  the  Lehigh  River. 

Annual  Report,  Pennsylvania  Geological  Survey,  1886,  Pt.  4,  pp.  1386—1408. 
This  is  an  important  paper,  giving  position  of  ore  beds,  methods  of  mining 
and  manufacture. 
CONRAD  E.  HESSE.     The  Paint  Ore  Mines  at  Lehigh  Gap. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XIX,  1890,  p.  321. 
C.  W.  HAYES  and  E.  C.  ECKEL.     Occurrence  and  Development  of  Ocher  Deposits 
in  the  Cartersville  District,  Georgia. 

Bulletin  No.  213,  Series  A,  Economic  Geology,  XXIV,  U.  S.  Geol.  Survey, 
1902. 

7.  ILMENITE;  MENACCANITE;  OR  TITANIC  IRON. 

Composition. — FeTiO3,  =  oxygen,  31.6  per  cent;  titanium,  31.6 
per  cent;  iron,  36.8  per  cent;  hardness,  5  to  6;  specific  gravity,  4.5 
to  5 ;  color,  iron-black  with  a  submetallic  luster  and  streak ;  opaque. 
Differs  from  magnetite,  which  it  somewhat  resembles,  by  its  crys- 
talline form  and  by  its  influencing  but  slightly  the  magnetic 
needle. 

Mode  oj  occurrence. — Its  common  form  is  massive,  or  in  thin  plates 
or  laminae,  or  as  small  granules,  sometimes  disseminated  through 
the  mass  of  rock  or  loose  in  the  sand.  In  microscopic  forms  it  is 
a  common  constituent  of  eruptive  rocks,  both  acid  and  basic.  Not 
infrequently  it-  occurs  in  large  masses,  closely  resembling  magnetic 
iron  ore.  In  the  parish  of  St.  Urbian,  Bay  St.  Paul,  Province  of 
Quebec,  Canada,  is  such  a  bed,  stated  to  be  90  feet  in  thickness  and 
to  have  been  traced,  with  some  interruptions,  for  a  mile.  The  bed 
is  in  anorthite  feldspar  rock  of  Laurentian  age.  The  ore  is  quite 
pure,  and  carries  some  48.6  per  cent  titanic  acid.  At  Kragero,  in 
Norway,  the  mineral  occurs  in  the  form  of  veins  in  diorite.  In 
Virginia  it  is  found  in  granular  masses^  containing  apatite. 

Uses. — The  mineral  has  as  yet  proved  of  little  economic  impor- 
tance. It  is  stated  that  the  presence  of  titanium  has  an  important 
bearing  upon  the  qualities  of  iron  and  steel,  but  as  such  it  is  beyond 
the  scope  of  this  work.  As  long  -a.go  as  1846  an  attempt  was  made 
to  use  a  ferrocyanide  of  titanium  as  a  green  paint  in  place  of  the 
poisonous  arsenical  greens.  Later  (1861)  other  patents  were  granted 
in  England  for  titanium  pigments.  A  deep-blue  enamel,  resembling 
the  smalt  prepared  with  the  oxide  of  cobalt,  has  also  been  prepared 


OXIDES.  113 

from  it,  but  as  yet  the  mineral,  though  abundant  and  cheap,  has 
practically  no  economic  use.  In  the  course  of  time  it  will  probably 
be  utilized  in  the  manufacture  of  titanium  steel. 

8.  RUTILE. 


Composition  and  general  properties.  —This  mineral  is  a  titanium 
oxide,  having  the  formula  TiO2,  =  oxygen,  40  per  cent,  and  titanium, 
60  per  cent.  The  hardness  is  6  to  6.5;  specific  gravity,  4.18  to  4.25; 
luster,  metallic  adamantine,  opaque  as  a  rule,  rarely  transparent; 
color,  reddish  brown  to  red,  rarely  yellowish,  blue,  or  black;  streak, 
pale  brown.  The  mineral  crystallizes  in  the  tetragonal  system, 
and  is  commonly  found  in  prismatic  forms  longitudinally  striated, 
and  often  in  geniculate  or  knee-shaped  twins.  Not  infrequently  it 
occurs  in  the  form  of  fine  thread-like  or  acicular  crystals  penetrating 
quartz.  It  is  insoluble  in  acids  and  infusible  before  the  blowpipe. 

Brookite  and  octahedrite  have  the  same  composition  and  essen- 
tially the  same  physical  properties  and  mode  of  occurrence. 

Mode  of  occurrence.  — Rutile  occurs  mainly  in  the  older  crystalline 
granitic  rocks,  schists,  and  gneisses,  but  is  also  found  in  metamorphic 
limestones  and  dolomites,  sometimes  in  the  mass  of  the  rock  itself, 
or  in  the  quartz  of  veins.  Being  so  nearly  indestructible  under  nat- 
ural conditions,  it  gradually  accumulates  in  the  debris  resulting 
from  rock  decomposition,  and  is  hence  not  an  uncommon  constit- 
uent of  auriferous  sands. 

Localities.- — Some  of  the  better-known  localities  are  the  apatite 
deposits  of  Kragero,  in  Norway;  Yrieux,  near  Limoges,  in  France; 
the  Ural  Mountains;  and  the  Appalachian  regions  of  the  United 
States.  Graves  Mountain,  Georgia;  Randolph  County,  Alabama, 
and  the  Magnet  Cove  region  of  Arkansas  are  celebrated  localities. 

Near  Roseland,  Nelson  County,  Virginia,  rutile  is  found  dissemi- 
nated a  coarsely  crystalline  quartz  feldspathic  rock  of  evident  igneous 
origin.  The  mineral  occurs  mainly  in  the  form  of  small  granules 
of  all  sizes  up  to  2  or  3  millimeters  in  diameter,  which  are  sometimes 
disseminated  with  remarkable  uniformity  throughout  the  feld- 
spathic ground-mass  or  again  segregated  in  the  quartz;  rarely  pieces 
of  several  pounds'  weight  have  been  found  loose  in  the  soil.  The 
rock  is  remarkably  free  from  other  minerals  than  those  mentioned, 


U4  THE  NON-METALLIC  MINERALS. 

and  there  is  a  complete  absence  of  titaniferous  iron  or  heavy  con- 
stituents such  as  would  render  -difficult  a  separation  of  the  rutile  by 
the  ordinary  gravimetric  methods. 

The  ore  is  mined  from  open  cuts,  stamped  and  concentrated  on 
the  premises,  the  yield  varying  from  5  to  25  per  cent -of  rutile  concen- 
trates in  the  form  of  a  beautiful  resinous  red-brown  sand. 

Uses. — Much  attention  has  of  late  been  paid  by  metallurgists  to  the 
question  of  the  influence  of  titanium  on  cast  iron  and  steel.  The 
consensus  of  opinion  at  date  of  writing  is  apparently  to  the  effect 
that  such  is  beneficial.  According  to  A.  J.  Rossi  cast  iron  may  be 
improved  in  both  transverse  and  tensile  strength  from  20  to  30  per 
cent  by  the  addition  of  small  amounts  of  titaniferous  alloys.  Quite 
similar  results  follow  its  use  in  steel.  Small  amounts  of  titanium 
are  also  used  in  the  manufacture  of  artificial  teeth  and  of  porcelain 
ware,  in  both  cases  serving  as  a  pigment.  It  is  also  used  in  dyeing 
leathers  and  in  the  preparation  of  the  "carbons"  used  in  electric 
lights. 

Until  the  establishment  of  the  mill  at  Roseland,  Virginia,  some 
200  to  300  pounds  only  of  rutile  were  annually  produced  in  the 
United  States,  and  40,000  to  90,000  pounds  in  Norway,  the  average 
value  being  about  10  cents  per  pound.  The  Virginia  works  are 
capable  of  producing  from  1,000  to  2,000  pounds  per  day. 

BIBLIOGRAPHY. 

G.  P.  MERRILL.     Rutile  Mining  in  Virginia. 

Engineering  and  Mining  Journal,  March  8,  1902. 
THOS.  WATSON.     Mineral  Resources  of  Virginia. 

9.    CHROMITE. 

Chromite  is  a  mineral  of  the  spinel  group,  and  of  the  theoretical 
formula  FeOjQ^Os.  This  equals  a  percentage  of  chromic  oxide 
of  68  per  cent,  but  the  natural  mineral  has  often  alumina  and  ferric 
iron  replacing  a  part  of  the  chromium,  so  that  50  per  cent  chromic 
oxide  more  nearly  represents  the  general  average.  The  ordinary 
demand,  it  may  be  stated,  is  for  an  ore  carrying  45  per  cent  and 
upward  of  chromic  acid. 

The  analyses  given  on  the  next  page  will  serve  to  show  the  vary- 
ing character  of  the  mineral. 


OXIDES. 


"3 

g  1 

> 
w        r- 

ON        t- 

•»        O         to       *- 
O         00         OC 

810        N         O        O         r 
\O          ro       vQ          H          i 

0         O 
o       •* 

o 

« 

8C 
c 

JN         ON         C 
h         ON         C 

?N           O             <N             C 

JN         O          ON         C 

M 

£8     S    8^    £    £    5 

>.         ON 
*         ON 

ON 

ON 

i 
i 

to 

o" 

O 

<u 

ON 
0 

;     : 

!      \o       ^        •        • 

ON 
O 

i 

+ 

o5 
o' 

o 

0 

10 

| 

•       o 

!       °        !       l°       ! 

o 

10 

I 

o 

:    «     .    10 

C 
<u 

Cfl 

10          C 
00           v/ 

4      c 

•S              0 

•)           O) 

8    C3- 

q       o        ON      M         | 

!>.           l>-           P!             CS                • 

gj 

M 

to 

ON 

0 

I 

g 

8 

q       « 

>O             H 

00          O         OC 

r-       00        ^C 

Tj-            H              C* 

!!>.          10                                      00            f. 
C4              ON                                             00              C 

•>•      «0     ''eo  '      ••           •        CO         c 

•)           (N             C)                •                •             W             0 

o       ! 

, 

• 

6 

2.     P 

I 
'         t~ 

:     M     3.    ct     ; 

8 

p 

•              U 

•J 

")               •                 • 

•         O         »o        10          • 

• 

6 

O               H 

00         i/ 

• 

O          t/ 

•>          «            H 

•5         O         00          C 

CN 

ON         TO        O           C^           T^"         I, 

N            Tt"            O              IO            M              I-H              lj 

o        O 
o        0 

s? 

c 

0 

ON         C 
V 

IN          ON          T! 

•N        10        T] 

IO            M              U 

Tf           10          ^ 

•}         ON         t^         M           d          10        v^ 
T}~        c^       10       10       to       ti 

5              Tf 

0        \O 

^o 

1 

t~~. 

M 

N            r- 

H 

-        O           C^           r^ 

q      vq       o 
i       N        ci        v/ 

>        O  -       *                      ON         ON         C 

^         ON                      <N           ro        OC 

1         f5         O^                      CS           O\         C 

M                                                M 

rTj- 
q 

is        to 

1  v 

M 

-       ^ 

9 

(S 

O          O 

00          0 

10            H 

M                   Tj 

O          vo         0 
-       o         f.        cs 

t^-         ro         N         00          10        vc 

) 
) 

8              H 

^           *"*            £ 

M 

•JO          t>-         ON        04          10        C 

M 

> 

1 

•         • 

:     :     :     :     : 

6   1 

• 

: 

1  A 

i     ; 

:      .      .      ! 

j 

I 

\ 

h- 

i 

Near  Athens,  Greece  
Bare  Hills,  Baltimore.  Maryland. 

Price's  Creek,  Yancey  County,  N< 
Franklin,  Macon  Countv.  North  ( 

oJ 

i  i  i 

J2     g      : 
C     5     -§ 

rt 

c"      oT      c 

13  ° 

J    U     5 

S    J*    .3 

^      PQ      W 

Ekaterinburg,  Russia  
Western  Transvaal,  South  Africa. 
Chester  County,  Pennsylvania.  .  . 
Monterey  County,  California  
Lancaster  County,  Pennsylvania. 
Do.. 

•J 

I 

II 6  THE  NON-METALLIC  MINERALS, 

Chromite,  like  magnetic  iron,  is  black  in  color  and  of  a  metallic 
luster,  but  differs  in  being  less  readily  if  at  all  attracted  by  the  magnet. 
On  a  piece  of  ground  glass  or  white  unglazed  porcelain  it  leaves  a 
brown  mark,  and  fused  with  borax  before  the  blowpipe  it  gives  a 
green  bead. 

Occurrence  and  origin. — Chromite  is  a  common  constituent  in  the 
form  of  disseminated  granules  of  basic  eruptive  rocks  belonging  to 
the  peridotite  and  pyroxenite  groups  and  in  the  serpentinous  and 
talcose  rocks  which  result  from  their  alteration.  It  is  never  found  in 
true  veins  or  beds,  though  sometimes  in  segregated,  nodular  masses 
somewhat  simulating  veins  on  casual  inspection.  The  more  common 
form,  as  noted  above,  is  that  of  small  masses  and  detached  granules, 
which,  when  freed  from  the  inclosing  rock,  form  the  ore  known  as 
chrome  sand. 

It  is  stated  by  J.  H.  Pratt,  that  in  North  Carolina  chromite  occurs 
under  conditions  very  similar  to  those  of  corundum,  i.e.,  at  and  near 
the  line  of  contact  between  the  intrusive  peridotites  and  gneissic 
rocks.  It  is  thought  probable  by  Pratt  that  the  mineral  was  held 
in  solution  in  the  molten  magma  at  the  time  of  its  intrusion  into  the 
country  rock.  Such  a  magma,  he  states  1  would  be  like  a  saturated 
liquid,  and  as  it  began  to  cool  the  minerals  would  crystallize,  not 
according  to  their  fusibility,  but  according  to  their  solubility  in  the 
molten  material.  The  more  basic  minerals  (in  this  case  chromite) 
being,  according  to  the  general  law  of  cooling  and  crystallizing  magmas, 
the  least  soluble,  would  be  the  first  to  separate  out.  These  early 
crystallizations  would  naturally  take  place  near  the  line  of  contact 
of  the  eruptive  material  with  the  previously  solidified  rocks,  since 
cooling  would  be  here  first  manifested.  Convection  currents  would 
tend  to  bring  new  supplies  of  material  and  hence  the  deposits  would 
become  enriched.  F.  Cirkel  2  reports  a  wide  variation  in  the  char- 
acter of  the  deposits  in  Canada,  no  two  being  alike.  In  some  cases 
the  ore  occurs  in  disseminated  granules  and  in  others  in  lenses  or 
pocket-shaped  deposits  as  knolls  or  kidney-shaped  accumulations, 
distributed  through  cracks  in  solid  serpentine,  or  segregated  and  in 
contact  with  intrusions  of  granitic  rock.  This  author,  however, 

1  Transactions  of  the  Am.  Inst.  of  Mining  Engineers,  XXIX,  1899  (1900),  p.  25. 

2  Report  on  Chrome  Iron  Ore  Deposits  in  the  Eastern  Townships  of  Quebec. 
Ottawa,  1909. 


FIG.  i. — Segregation  Veins  of  Chrome  Iron,  near  Rustenburg,  South  Africa. 
[From  Trans.  Geological  Society  of  South  Africa.] 


FIG.  a. — Open  Cut  Manganese  Mine,  Crimora,  Virginia. 
[After  Thos.  Watson,  Mineral  Resources  of  Virginia.] 

PLATE  IX. 

[Facing  page  116.] 


OXIDES.  H7 

finds  nothing  to  support  an  oft-repeated  assertion  to  the  effect  that 
all  of  the  commercially  important  deposits  lie  along  the  contact 
of  the  serpentine  with  the  granite  or  other  rocks;  in  fact,  some  of 
the  larger  deposits  are  far  removed  from  such  contacts. 

In  the  Transvaal,  South  Africa,  the  deposits  occur  associated 
with  igneous  rocks  rich  in  hypersthene  and  poor  in  plagioclase  feld- 
spars. They  occur  in  what  are  described  as  fairly  well-defined 
bedded  veins  with  dip  and  strike  roughly  analogous  to  that  of  the 
neighboring  sedimentary  beds,  the  thickness  of  the  veins  varying 
from  5  feet  downward,  and  usual1  y  maintaining  a  fairly  uniform 
width  for  some  distance.  The  following  section  is  given  showing 
the  occurrence  at  Mooihoek : 

Ft.  In. 

1.  Fine-grained  friable  weathered  dark  greenish  noritic  rock,  rich  in  rhombic 

pyroxene  with  scattered  chromite  grains o  o 

2.  Chrome  iron  vein  composed  of  dark  almost  black  granular  ore i  o 

3.  Fine-grained  granular  dirty  greenish  hypersthenite 2  4 

4.  Black  fine-grained  friable  granular  chrome-iron  ore  with  small  lighter-colored 

irregular  patches -. 4  6 

5.  Dark  granular  slightly  greenish  hypersthenite  identical  with  No.  3 2  6 

6.  Vein  of  black  powdery  chrome-iron  ore  closely  resembling  No.  4 4  6 

7.  Granular  hypersthenite  with  scattered  grains  of  chromite. 

It  will  thus  be  seen  that  there  are  three  separate  sheets  of  the 
chrome  ore  with  a  collective  thickness  of  about  10  feet.  The  presence 
in  the  country  rock  of  scattered  grains  of  chromite  shows,  however, 
that  the  deposits  are  not  in  true  veins,  but  evidently  segregations  out 
of  the  molten  magma,  as  in  Canada  and  North  Carolina.  In  all  of 
these  cases  it  is  evident  that  the  chromite  deposits  are  to  be  considered 
as  original  and  not  due  to  the  alteration  of  the  peridotite  into  serpen- 
tine. Baumgartel,1  it  is  true,  describes  secondary  chromites  origin'1 1- 
ing  through  the  decomposition  of  chromiferous  diopsides  in  Bosnian 
peridotites,  but  there  is  nothing  to  show  that  such  secondary  deposits 
ever  occur  of  such  magnitude  as  to  be  of  commercial  importance. 

The  principal  domestic  sources  of  chromium  are  at  present  Del 
Norte,  San  Luis  Obispo,  Shasta  and  Placer  counties  in  California, 
though  formerly  mines  in  Lancaster  County,  Pennsylvania,  and 
the  Bare  Hills  region  near  Baltimore  were  very  productive.  The 
American  supply  of  material  is  to-day  derived  very  largely  from 
Canadian  sources,  the  distribution  of  the  mines  being  coincident 

1  Tschermak's  Min.  u.  Petr.  Mittheil.,  XXIII,  1904,  p.  393. 


n8  THE  NON-METALLIC  MINERALS. 

with  that  of  the  Cambrian  serpentines,  from  which  is  derived  the 
asbestos  and  which  occur  in  a  belt  extending  from  Southern  Vermont 
to  Gaspe  in  the  Province  of  Quebec.  Along  the  course  of  this  belt 
chromite  exists  at  several  points,  and  many  attempts  have  been 
made  at  mining,  but  in  most  instances  the  mineral  has  been  found 
in  too  small  a  quantity  to  be  of  commercial  value.  The  most  im- 
portant field  is  in  what  is  known  as  the  Thetford  Black  Lake  area, 
and  especially  in  the  township  of  Coleraine.  The  deposits  are  of 
an  exceedingly  irregular  character,  having  no  definite  form  and  no 
tendency  to  adhere  to  dimensions  in  special  directions  and  apparently 
have  no  relation  to  each  other.  Masses  of  ore  have  been  found 
varying  up  to  50  or  75  feet  in  greatest  diameter. 

On  account  of  the  irregular  character  of  the  deposits  there  has 
always  been,  and  presumably  always  will  be  a  considerable  amount 
of  uncertainty  in  mining  and  little  dependence  can  be  placed  upon 
surface  indications.  The  quality  of  ore  that  can  be  worked  to  com- 
mercial advantage  is  naturally  widely  variable.  Cirkel  states  that 
in  the  Canadian  area  a  rock  must  yield  at  least  20  per  cent  of 
chromite  in  order  to  be  utilized. 

Chrome  ore  is  also  found  in  Newfoundland;  the  Russian  Urals; 
in  Asia  Minor  and  European  Turkey,  and  in  Macedonia;  in  Aus- 
tralia, New  Zealand  and  New  Caledonia,  in  all  cases  so  far  as  known 
the  deposits  occurring  in  peridotite  or  serpentine. 

Uses. — Chromium  is  used  in  the  production  of  the  pigments 
chrome-yellow,  orange,  and  green,  and  in  the  manufacture  of  bichro- 
mate of  potash  for  calico  printing  and  certain  forms  of  electric  bat- 
teries. A  small  amount  is  also  used  in  the  production  of  what  is 
known  as  chrome  steel. 

Chrome-ore  linings  for  reverberatory  furnaces  have  been  suc- 
cessfully adopted  in  French,  German,  and  Russian  steel  works. 
The  bottom  and  walls  of  the  furnace  are  lined  with  the  ore  in  large 
blocks,  united  by  a  cement  formed  by  two  parts  of  ore  finely  ground, 
and  one  part  of  lime  as  free  from  silica  as  possible. 

The  best  composition  used  for  lining  reverberatory  furnaces  is 
found  to  be  from  36  to  40  per  cent  of  chromic  oxide,  18  to  22  per  cent 
of  clay,  9  to  10  per  cent  of  magnesia,  and  at  most  5  per  cent  of  silica.1 

1  Journal  of  the  Iron  and  Steel  Institute,  1895,  pp.  506,  507.  Abstract  from  L'Echo 
des  Mines,  XXI,  p.  584. 


OXIDES.  119 

Chromite  has  been  also  successfully  used  as  a  hearth-lining  for 
copper-smelting  purposes. 

"The  chrome  industry  in  America  originated  in  the  discovery 
in  1827  of  chrome  ore  in  the  serpentine  of  the  Bare  Hills  region, 
some  6  miles  north  of  Baltimore,  Maryland.  Mr.  Isaac  Tyson,  Jr., 
began  the  manufacture  of  'chrome-yellow'  from  this  material  in 
Baltimore,  in  1828.  Finding  that  the  chrome  ore  was  always  con- 
fined to  serpentine,  Mr.  Tyson  began  a  systematic  examination  of  the 
serpentine  areas  of  Maryland,  which  could  be  easily  traced  by  the 
barren  character  of  the  soil  which  they  produce.  A  narrow  belt  of 
serpentine  extends  across  Montgomery  County,  and  while  chrome 
ore  is  occasionally  found  in  it,  nothing  of  economic  importance  has 
ever  been  discovered  in  Maryland  south  of  the  areas  known  as 
'Soldiers'  Delight'  and  'Bare  Hills.'  Northeastward,  however,  the 
deposits  become  much  richer.  The  region  near  Jarrettsville  was 
productive,  and  thence  the  serpentine  was  traced  to  the  State  line 
in  Cecil  County.  Near  Rock  Springs  the  serpentine  turns  and 
follows  the  State  line  eastward  for  15  miles.  On  the  Wood  farm, 
half  a  mile  north  of  the  State  line  and  5  miles  north  of  Rising  Sun, 
in  Cecil  County,  Mr.  Tyson  discovered  in  1833  a  chromite  deposit, 
which  proved  to  be  the  richest  ever  found  in  America.  This  prop- 
erty was  at  once  purchased  and  the  mine  opened.  At  the  surface 
it  was  30  feet  long  and  6  feet  wide,  and  the  ore  so  pure  that  each 
10  cubic  feet  produced  a  ton  of  chrome  ore,  averaging  54  per  cent 
of  chrome  oxide.  The  ore  was  hauled  12  miles  by  wagon  to  Port 
Deposit,  and  shipped  thence  by  water  to  Baltimore  and  Liverpool. 
At  a  depth  of  20  feet  the  vein  narrowed  somewhat,  but  immediately 
broadened  out  again  to  a  length  of  120  feet  and  a  width  of  from 
10  to  30  feet.  The  Wood  Mine  was  worked  almost  continuously 
from  1828  to  1881,  except  between  the  years  1868  and  1873.  During 
that  time  it  produced  over  100,000  tons  of  ore  and  reached  a  depth 
of  600  feet. 

"Between  1828  and  1850  Baltimore  supplied  most  of  the  chrome 
ore  consumed  by  the  world;  the  remainder  came  from  the  serpen- 
tine deposits  and  platinum  washings  of  the  Urals.  The  ore  was  at 
first  shipped  to  England.  After  1850  the  foreign  demand  for  Balti- 
more ore  declined  gradually  till  1860,  since  which  time  almost  none 
has  been  shipped  abroad.  The  reason  for  this  was  the  discovery  in 


120  THE  NON-METALLIC  MINERALS. 

1848  of  great  deposits  of  chromite  near  Brusa,  57  miles  southwest  of 
Constantinople,  by  Professor  J.  Lawrence  Smith,  who  was  employed 
by  the  Turkish  Government  to  examine  the  mineral  resources  of 
that  country.  Other  deposits  were  also  discovered  by  him  15  miles 
farther  south,  and  near  Antioch." 

Between  1880  and  1892  the  annual  production  of  chromite  in  the 
United  States  varied  between  1,500  and  3,000  tons.  During  the 
succeeding  decade  the  production  was  greatly  diminished.  Statistics 
for  1908  show  an  output,  wholly  from  California,  of  but  280  long 
tons,  valued  at  about  $20.00  per  ton.  Some  7,876  tons  were  im- 
ported during  this  same  year.  The  principal  sources  of  supply 
are  now  Canada,  Greece,  New  Caledonia,  New  South  Wales,  Russia 
and  Turkey.  The  Canadian  output  during  1908  is  placed  at  7,225 
tons. 

BIBLIOGRAPHY. 

Lake  Chrome  and  Mineral  Company,  of  Baltimore  County. 

American  Mineral  Gazette  and  Geological  Magazine,  I,  April  i,  1864,  p.  253. 
HARRIE  WOOD.     Chromite  and  Manganese. 

Mineral  Products  of  New  South  Wales,  Department  of  Mines,  1887,  p.  42. 
Ueber  schwedisches  Chromroheisen  und  Martinchromstahl. 

Berg-  und  Huttenmannische  Zeitung,  XLVII,  1888,  p.  267. 
Die  Chromeisenerz-Lagerstatten  Neuseelands. 

Berg-  und  Huttenmannische  Zeitung,  XLVII,  1888,  p.  375. 
Chromite  Mined  at  Cedar  Mountain. 

Eighth  Annual  Report  of  the  State  Mineralogist  of  California,  1888,  p.  32. 
Chrome  Iron  Ore  from  Orsova. 

Journal  of  the  Iron  and  Steel  Institute,  1889,  p.  316. 
Chrome  Iron  in  Shasta  and 'San  Luis  Obispo  Counties. 

Tenth  Annual  Report  of  the  State  Mineralogist  of  California,  1890,  pp.  582 
and  638. 
Chrome  Iron. 

Twelfth    and    Thirteenth    Reports    of    the    State  Mineralogist  of  California, 
1894  and  1896. 
Chromic  Iron:  Its  Properties,  Mode  of  Occurrence,  and  Uses. 

Journal  of  the  General  Mining  Assoication  of  the  Province  of  Quebec,  1894-95, 
p.  108. 
W.  F.  WILKINSON.     Chrome  Iron  Ore  Mining  in  Asia  Minor. 

Engineering  and  Mining  Journal,  LX,  1895,  P-  4- 
WM.  GLENN.     Chrome  in  the  Southern  Appalachian  Region. 

Transactions  of  the   American   Institute  of  Mining   Engineers,  XXV,  1895, 
p.  481. 

GEORGE  W.  MAYNARD.     The  Chromite  Deposits  on  Port  au  Port  Bay,  New  Found- 
land. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXVII,  1897, 
p.  283. 


OXIDES. 


121 


J.  H.  PRATT.     The  Occurrence,  Origin,  and  Chemical  Composition  of  Chromite,  with 
especial  reference  to  the  North  Carolina  Deposits. 

Transactions  of  the  American  Institute  of  Mining  Engineers,   XXIX,   1899, 
p.  17. 

F.  CIRKEL.     Report  on  Chrome  Iron  Ore  Deposits  in  Eastern  Townships.     Province 
of  Quebec,  Ottawa,  1909. 


10.      MANGANESE     OXIDES. 

The  element  manganese  exists  in  nature  under  many  different 
forms,  of  which  those  in  combination  as  oxides,  carbonates,  and 
silicates  alone  need  concern  us  in  this  work.  The  principaF  known 
oxides  are  Manganosite  (MnO);  Hausmannite  (MnO,Mn2O3); 
Braunite  (3Mn2O3rMnSiO3) ;  Polianite  (MnO2);  Pyrolusite  (MnO2); 
Manganite  (Mn2O3,H2O);  Psilomelane  (H4MnO5);  and  Wad,  the 
last  being,  perhaps,  an  earthy  impure  form  of  psilomelane.  To  this 
list  should  be  added  the  mineral  franklinite,  a  manganiferous  oxide 
of  iron  and  zinc.  Of  these,  the  first  named,  manganosite,  is  rare, 
having  thus  far  been  reported  only  in  small  quantities  associated 
with  other  oxides  in  Wermland,  Sweden.  The  other  forms  are 
described  somewhat  in  detail  as  below.  It  should  be  stated,  how- 
ever, that  with  the  exception  of  the  well-crystallized  forms  it  is 
often  difficult  to  discriminate  between  them,  as  they  occur  admixed 
in  all  proportions,  and,  moreover,  one  variety,  as  pyrolusite,  may 
result  from  the  alteration  of  another  (manganite) .  The  better  defined 
species  may  be  separated  from  one  another  by  their  comparative 
hardness,  streak,  and  hydrous  or  anhydrous  properties,  as  shown 
in  the  accompanying  table. 


Variety. 

Hardness. 

Specific 
Gravity. 

Color. 

Streak. 

Anhydrous 
or  Hydrous. 

Franklinite.  .  .  . 
Hausmannite  .  . 

5  •  5  to  6  .  5 

T              5-5 

5       to  5.  22 
47        4   85 

Iron-black  
Brown-black 

Reddish      brown      to 
black  

Anhydrous. 
Do 

Braunite  
Polianite  .  .  . 

6            6.5 

6             6    <5 

4-7        4-85 
48        49 

Brown-black  to  steel- 
.gray  

Brown-black.  ...... 
Black 

Do. 
Do 

Pyrolusite  
Manganite.  ... 
Psilomelane.  ,  . 

2             2.5 
4 
5-6        3-7 

4.8 
4-2        4-4 

4-7 

Iron-black   to   steel- 
gray  or  bluish.  .  ,  . 
Dark     steel-gray   to 
iron-black  
Iron-black   to    steel- 
gray  

Black  or  blue-black. 
Red-  brown  to  black.  , 
Brown-  black.  .  .  . 

a  Do. 
Hydrous. 
Do 

a.  Usually  yields  water  in  closed  tube. 


122  THE  NON-METALLIC  MINERALS. 

The  chemical  relationship  of  the  ores  as  found  in  nature  is  thus 
set  forth  by  Penrose : l 


Chemical  Composition.                        Anhydrous  Form. 

Hydrous  Form. 

Protoxide  (MnO)  .  .  . 

Manganosite  (MnO)  .  
Hausmannite  (MnjOJ  .  .. 
Braunite  (Mn  O  ) 

Pyrochroite  (MnO.H2O). 

Manganite  (Mn2O.yH2O). 
j  Psilomelane. 
\  Wad. 

Proto-sesquioxide  (Mn3O4)  . 

Peroxide  (MnO  ) 

Pyrolusite,  Pobanite  (MnO2) 

Manganese  oxides  frequently  occur  admixed  in  indefinite  pro- 
portions with  the  hydrous  oxide  of  iron,  limonite,  giving  rise  to  the 
manganiferous  limonites. 

Franklinite. — This  may  be  termed  rather  a  manganiferous 
ore  of  iron  and  zinc  than  a  true  ore  of  manganese.  Nevertheless, 
as  the  residue  after  the  extraction  of  the  zinc  is  used  in  the  manu- 
facture of  spiegeleisen,  we  may  briefly  refer  to  it  here.  The  mineral 
occurs  in  rounded  granules  or  octahedral  crystals  of  a  metallic 
luster  and  iron-black  color,  associated  with  zinc  oxides  and  silicates 
in  crystalline  limestones,  at  Franklin  Furnace,  New  Jersey.  It  bears 
a  general  resemblance  to  the  .mineral  magnetite,  but  is  less  readily 
attracted  by  the  magnet  and  gives  a  strong  manganese  reaction. 
Its  average  content  of  manganese  oxides  Mn2O3  and  MnO  is  but  from 
15  to  20  per  cent. 

Hausmannite. — This  form  of  the  ore  when  crystallized  usually 
takes  the  form  of  the  octahedron,  and  may  be  readily  mistaken  for 
franklinite,  from  which,  however,  it  differs  in  its  inferior  hardness, 
lower  specific  gravity,  and  in  being  unacted  upon  by  the  magnet. 
It  occurs  in  porphyry,  associated  with  other  manganese  ores,  in 
Thuringia;  is  also  found  in  the  Harz  Mountains;  Wermland, 
Sweden,  and  various  other  European  localities.  In  the  United 
States  it  is  reported  as  occurring  only  in  Iron  County,  Missouri. 
The  mineral  in  its  ideal  purity  consists  of  sesquioxide  and  protoxide 
of  manganese  in  the  proportion  of  69  parts  of  the  former  to  31  of 
the  latter.  Analyses  of  the  commercial  article  as  mined  are  not 
at  hand. 

Braunite. — This,  like  hausmannite,  crystallizes  in  the  form  of  the 
octahedron,  but  is  a  trifle  harder.  Chemically  it  differs,  in  that 
analyses  show  almost  invariably  from  7  to  10  per  cent  of  silica, 

1  Annual  Report  of  the  Geological  Survey  of  Arkansas,  I,  1890,  p.  541. 


OXIDES.  1 23 

though  as  to  whether  or  no  this  is  to  be  considered  an  essential 
constituent  it  is  as  yet  difficult  to  say.  Analyses  I  and  II,  on  p  124, 
show  the  composition  of  the  mineral  as  found.  The  ore  is  reported 
as  occurring  both  crystallized  and  massive  in  veins  traversing  por- 
phyry at  Oehrenstock  in  Ilmenau,  in  Thuringia,  near  Ilefeld  in  the 
Harz;  Schneeberg,  Saxony,  and  various  other  European  localities. 
Also  at  Vizianagram  in  India;  in  New  South  Wales,  Australia,  and 
in  the  Batesville  region,  Arkansas. 

Polianite. — Like  pyrolusite,  yet  to  be  noted,  this  form  of  the  ore 
is  chemically  a  pure  manganese  binoxide,  carrying  some  63.1  per 
cent  metallic  manganese  combined  with  36.9  per  cent  oxygen.  From 
pyrolusite  it  is  readily  distinguished  by  its  increased  hardness. 
So  far  as  reported,  it  is  a  rather  rare  form  of  manganese,  though 
possibly  much  that  has  been  set  down  as  pyrolusite  may  be  in 
reality  polianite. 

Pyrolusite  occurs  in  the  form  of  iron-black  to  steel-gray,  some- 
times bluish  opaque  masses,  granular,  or  commonly  in  divergent 
columnar  aggregates  sufficiently  soft  to  soil  the  fingers,  and  in  this 
respect  easily  separated  from  the  other  common  forms  excepting  wad; 
not  known  in  crystals  except  as  pseudomorph's  after  manganite. 
In  composition  it  is  quite  variable,  usually  containing  traces  of  iron, 
silica,  and  lime,  and  sometimes  barium  and  the  alkalies.  Analyses 
III  and  IV,  on  p.  124^  as  given  by  Penrose,  will  serve  to  show  the 
general  average.  This  is  a  common  ore  of  manganese,  and  is 
extensively  mined  in  Thuringia,  Moravia,  Bohemia,  Westphalia, 
Transylvania,  Australia,  Japan,  India,  New  Brunswick,  Nova 
Scotia,  and  various  parts  of  the  United  States. 

Manganite  differs  and  is  readily  distinguishable  from  the  other 
ores  thus  far  described,  in  carrying  from  3  to  10  per  cent  of  com- 
bined water,  which  can  readily  be  detected  when  the  powdered 
mineral  is  heated  in  a  closed  tube.  From  either  psilomelane  or 
pyrolusite  it  is  distinguished  by  its  hardness.  When  in  crystals  it 
takes  prismatic  forms  with  the  prism  faces  deeply  striated  longi- 
tudinally. Its  occurrence  is  essentially  the  same  as  that  of 
braunite. 

Psilomelane. — This  is,  with  the  possible  exception  of  pyrolusite, 
the  commonest  of  the  manganese  minerals.  The  usual  form  of 
occurrence  is  that  of  irregular  nodular  or  botryoidal  masses  em- 


124 


THE  NON-METALLIC  MINERALS. 


bedded  in  residual  clays.  It  is  readily  distinguished  from  manganite 
or  wad  by  its  hardness,  and. from  hausmannite.  braunite,  orpolianite 
by  yielding  an  abundance  of  water  when  heated  in  a  closed  tube. 
The  sample  from  the  Crimora  Mines  in  Virginia,  shown  in  Plate  X, 
is  characteristic.  The  composition  of  the  commercial  ore  is  given 
in  analyses  V,  VI,  and  VII,  below. 

Wad  or  Bog  Manganese  is  a  soft  and  highly  hydrated  form 
of  the  ore,  as  a  rule  of  little  value,  owing  to  impurities  (analysis  VIII). 
Asbolite  is  the  name  given  to  a  variety  of  wad  containing  cobalt  (see 
p.  28).  See  further  Rhodonite  and  Rhodochrosite,  pp,  159,  204. 


ANALYSES    OF    MANGANESE    ORES 


Constituents. 

Braunite. 

PyroJusite. 

Psiiome'ane. 

Wad. 

I. 

II. 

III. 

IV 

V 

VI 

VII 

VIII 

MnO  

87.47 
9.62 

86.95 
9-85 

90.15 

88.98 

8499 
1048 

80  27 

14.10 

63.46 

25  42 

o 

Fe,O,. 

2-55 

O-2I 

I  7C 

Cab 

O  3d. 

Q51 
4  35  *sO 
2.84 

BaO 

0.48 
0.18 

2.25 
0-95 

1.  12 
2.80 
2  05 

SiO,   

HO 





980 

6  oo 

3352 

*.±2\-r 

I.  Batesville  region   Arkansas. 

II.  Elgersburg  Germany. 

III.  Cheverie   Nova  Scotia. 

IV.  Cape  Breton. 


V  Batesvilie  region   Arkansas. 

VI  Schneeberg   Saxony 

VII  Cnmo-a  Virginia 

VIII.  Big  Harbor   Cape  Breton. 


Origin. — The  deposits  of  manganese  oxides  which  are  of  sufficient 
extent  to  be  of  commercial  importance  are  believed  to  be  in  all  cases 
of  secondary  origin;  that  is,  to  have  resulted  from  the  decompo- 
sition of  preexisting  manganiferous  silicate  constituents  of  the  older 
crystalline  rocks  and  the  subsequent  deposition  of  the  oxides  in 
secondary  strata.  Indeed  in  many  instances  the  ore  has  undergone 
a  natural  segregation,  owing  to  the  decomposition  of  the  parent 
rock  and  the  accumulate  of  the  manganese  oxide,  together  with 
other  difficult  soluble  constituents  in  the  residual  clay.  Thus  Penrose 
has  shown1  that  the  deposits  of  the  Batesville  (Arkansas)  region 
result  from  the  decay  of  the  St  Clan  limestone,  the  various  stages 
of  which  are  illustrated  in  the  accompanying  Plate  XI.  The  fresh 


Annual  Report  of  the  Geological  Survev  of  Arkansas,  I,  1890. 


C/J    htf 

2^~ 

li  r 


OXIDES.  125 

limestone,  as  shown  by  analysis,  contains  but  4.30  per  cent  manga- 
nese oxide  (MnO),  while  the  residual  clay  left  through  its  decom- 
position contains  14.98  per  cent  of  the  same  constituent. 

Occurrence. — As  above  noted,  the  ore  is  found  in  secondary  rocks, 
and  as  a  rule  in  greatest  quantities  in  the  clays  and  residual  deposits 
resulting  from  their  breaking  down.  The  usual  form  of  the  ore  is 
that  of  lenticular  masses  or  irregular  nodules  distributed  along  the 
bedding  planes,  or  heterogeneously  throughout  the  clay.  Penrose 
describes  the  Batesville  ores  as  sometimes  evenly  distributed  through- 
out a  large  body  of  clay,  but  in  most  places  as  being  in  pockets  sur- 
rounded by  clay  itself  barren  of  ore.  These  pockets  vary  greatly  in 
character,  being  sometimes  comparatively  solid  bodies  separated  by 
thin  films  of  clay,  and  containing  from  50  to  500  tons  of  ore;  some- 
times they  consist  of  large  and  small  masses  of  ore  embedded  together, 
and  again  at  other  times  of  small  grains,  disseminated  throughout 
the  clay.  In  the  Crimora  (Virginia)  deposits  the  ore  (psilomelane) 
is  found  in  nodular  masses  in  a  clay  resulting  from  the  decomposi- 
tion of  a  shale  which  has  been  preserved  from  erosion  through  sharp 
synclinal  folds. 

The  position  and  association  of  these  deposits  may  be  best 
understood  by  reference  to  the  accompanying  figures,1  Fig.  24  being 
that  of  the  ground  plan  of  the  immediate  vicinity  of  the  mine,  while 
Fig.  25  represents  cross-sections  along  the  lines  marked  in  Fig.  24. 
The  country  rock  is  a  massive  Potsdam  sandstone  overlaid  by  shales, 
the  latter  having  undergone  extensive  decomposition,  giving  rise  to 
clay  deposits  in  which  the  ore  now  occurs.  At  the  east,  along  the 
line  A  A  in  Fig/ 24,  the  sandstone  dips  to  the  westward.  At  CC  is 
an  anticline  from  which  the  beds  dip  both  toward,  the  west  and  east, 
forming  thus  a  syncline  the  axis  of  which  is  indicated  by  the  line  BB. 
The  sections  across  this  syncline  (Fig.  25)  show  the  accumulated 
clay  from  the  decomposition  of  the  shales,  in  which  the  man- 
ganese occurs.  The  ore  is  found  very  irregularly  distributed 
throughout  the  clay  in  lumps  and  masses  from  the  size  of  a  small 
pebble  to  those  weighing  a  ton  or  more.  The  basin  is  described 


1  From  Geological  Notes  on  the  Manganese  Ore  Deposit  of  Crimora,  Virginia. 
By  Charles  E.  Hall,  Trans.  Am.  Inst.  of  Min.  Engs.,  Vol.  XX,  1891,  pp.  47,  48. 


126 


THE  NON-METALLIC  MINERALS. 


FIG.  24. — Ground  plan  manganese  deposits,  Crimora,  Va. 
[After  C.  E.  Hall.] 


SECTION  No.  2 


SECTION  No.  4 


FIG.  25. — Sections  through  Crimora  manganese  deposits. 
[After  C.  E.  Hall.] 


IDEAL  SECTIONS  SHOWING  THE  FORMATION  or  MANGANESE-BEARING 

CLAY  FROM  THE  DECAY  OF  THE   SINCLAIR  LIMESTONE. 

Brrn 
MANGANESE-BEARING  CLAY  L_UIZARD  LIMESTONE 

E3  ST.CLAIR  LIMESTONE  L^JSACCHAROIDAL  SANDSTONE 

FIG.I.     ORIGINAL  CONDITION  Or  THE    ROCKS. 


i    •  i 


•*~l       I 


_,     I      , I _J — , — L 


"i~      r~ 


J L 


JL.-...I-...  <    ...I 


FIQ. 2.  FIRST  STAGE  OF  DECOMPOSITION. 


FIG. 3.  SECOND  STAGE  OF  DECOMPOSITION. 


FIG.  4.  THIRD  STA6E  OF  DECOMPOSITION. 


PLATE   XI. 

Ideal  Sections  ic  Shew  Oigir  of  Manganese  through  Weathering  of  Limestone, 
(After  Penrose,  Ai><r,,  Kf,p.  Qecj.  Survey  of  Arkansas,  Vol.  I,  1892.] 

[Facing  page  126.] 


OXIDES.  127 

as  some  500  feet  in  width  and  800  to  900  feet  in  length,  the  ore-bearing 
clay  extending  to  a  maximum  depth,  so  far  as  determined,  of  300 
feet. 

The  manganese  appears  to  have  been  here  originally  disseminated 
throughout  the  sandstone  and  shales  and  to  have  leached  out,  pre- 
sumably as  a  carbonate,  by  percolating  water,  and  redeposited  in 
the  basin,  where  the  flow  was  retarded  for  a  sufficient  time  for  oxida- 
tion to  take  place. 

In  Cuba,  maganese  is  found  in  the  province  of  Santiago,  the 
principal  occurrence  being  in  a  belt  lying  back  of  the  Sierra  Maestra 
and  extending  from  the  vicinity  of  Guantanamo  upon  the  east  to 
Manzanillo  upon  the  west.  The  ore,  which  may  be  either  manganite, 
pyrolusite,  or  wad,  singly  or  all  together,  occurs  as  a  rule  upon  hills 
or  knolls  composed  of  sedimentary  rocks — sandstones  and  lime- 
stones— in  disconnected  or  pocket  deposits  and  under  such  con- 
ditions as  to  point  unmistakably  to  an  origin  through  the  influence 
of  circulating  waters.  The  ore  is  often  associated  with  a  hard 
jasper,  or  "bayate,"  occurring  in  large  masses,  or  in  the  form  of 
disseminated  nodules  or  veinlets  in  the  ore.  The  occurrence  and 
association  are  such  as  to  indicate  that  the  two  substances  were 
deposited  nearly  contemporaneously,  and  from  the  water  of  hot 
springs. 

Branner  has  described  the  maganese  (psilomelane)  deposit  of 
Bahia,  Brazil,  as  occurring  in  the  form  of  a  sheet  or  bed  of  from  a 
few  decimeters  to  ten  meters  thickness,  standing  at  an  angle  of  60° 
in  decomposed  mica  schist.  (Fig.  26.) 

Bog  manganese  is  described  as  occurring  in  an  extensive  deposit 
near  Dawson  settlement,  Albert  County,  New  Brunswick,  on  a 
branch  of  Weldon  Creek,  covering  an  area  of  about  25  acres.  In 
the  center  it  was  found  to  be  26  feet  deep,  thinning  out  toward 
the  margin  of  the  bed.  The  ore  is  a  loose,  amorphous  mass,  which 
could  be  readily  shoveled  without  the  aid  of  a  pick,  and  contained 
more  or  less  iron  pyrites  disseminated  in  streaks  and  layers,  though 
large  portions  of  the  deposit  have  merely  a  trace.  The  bed  lies  in  a 
valley  at  the  northern  base  of  a  hill,  and  its  accumulation  at  this 
particular  locality  appears  to  be  due  to  springs.  These  springs  are 
ftill  trickling  down  the  hillside,  and  doubtless  the  process  of  pro- 


128 


THE  NON-METALLIC  MINERALS. 


ducing  bog  manganese  is  still  going  on.1     A  bed  of  manganese  ore 
in  the  government  of  Kutais,  in  the  Caucasus,  is  described  as  occur- 


W 


FIG.  26. — Sections  of  manganese  deposit  near  Bahia,  Brazil. 
[After  Branner,  Transactions  of  the  American  Institute  of  Mining  Engineers.] 

ring  in  nearly  horizontally  lying  Miocene  sandstones.     The  ore  is 
pyrolusite*  and  the  bed  stated  as  being  6  to  7  feet  in  thickness.2 

Mining  and  preparation. — The  mining  and  preparation  of  man- 
ganese ores  is,  as  a  rule,  a  comparatively  simple  process.  At  the 
Crimora  (Virginia)  mines  the  material  is  excavated  by  means  of 
shafts  and  tunnels,  and  taken  to  the  surface,  where  it  is  crushed, 
washed,  screened,  and  dried  for  shipment.  The  machinery  all 
works  automatically,  and  the  ore  is  not  handled  after  having  once 
passed  into  the  crusher.3 

1  Annual  Report  of  the  Geological  Survey  of  Canada,  VII,  1894,  p.  146  M. 

2  F.  Drake,  Transactions  of  the  American  Institute  of  Mining  Engineers,  XXV, 
1898,  p.  131. 

3  The  washing  plant  and  a  vertical  section  of  the  works  of  the  Crimora  Mines  are 
given  in  the  Engineering  and  Mining  Journal  for  March  22,  1890,  the  same  having 
drawn  for  its  information  on  the  American  Manufacturer  of  Pittsburg.     (Date  not 
given.) 


OXIDES. 


129 


Uses. — The  various  uses  to  which  manganese  and  its  compounds 
are  put  may  be  divided  into  three  classes:  Alloys,  oxidizers,  and 
coloring  materials.  Each  of  these  classes  includes  the  application 
of  manganese  in  sundry  manufactured  products,  or  as  a  reagent 
in  carrying  on  different  metallurgical  and  chemical  processes.  The 
most  important  of  these  sources  of  consumption  may  be  summarized 
as  follows: 


Alloys 


Oxidizers 


f  Spiegeleisen 

Ferromanganese  . 


Alloys  of  manganese  and  iron. 


Manganese  bronze 


Silver  bronze. . . 


Alloys  of  manganese  and  copper,  with  or 

without  iron. 

An  alloy  of  manganese,  aluminum,  zinc, 
and  copper,  with  a  certain  quantity  of 
silicon. 

Alloys   of  manganese   with   aluminum,    zinc,    tin,   lead,   mag- 
nesium, etc. 

Manufacture  of  chlorine. 
Manufacture  of  bromine. 
As  a  decolorizer  of  glass  (also  for  coloring  glass,  see  coloring 

materials). 

As  a  dryer  in  varnishes  and  paints. 
LeClanche's  battery. 
|  Preparation  of  oxygen  on  a  small  scale. 

(  Manufacture  of  disinfectants  (manganates  and  permanganates). 
{  Calico  printing  and  dyeing. 
Coloring  materials..  \  Coloring  glass> 
j  Paints 


Green. 
Violet. 


Besides  these  main  uses  a  certain  amount  is  utilized  as  a  flux  in 
smelting  silver  ores,  and,  in  the  form  of  its  various  salts,  is  employed 
in  chemical  manufacture  and  for  medicinal  purposes.  Pyrolusite 
and  some  forms  of  psilomelane  are  utilized  in  the  manufacture  of 
chlorine,  and  for  bleaching,  deodorizing,  and  disinfecting  purposes, 
also  in  the  manufacture  of  bromine. 

In  glass  manufacture  the  manganese  is  used  to  remove  the  green 
color  caused  by  the  presence  of  iron,  and  to  impart  violet,  amber, 
and  black  colors. 

The  amount  of  manganese  actually  used  for  other  than  strictly 
metallurgical  purposes  in  the  United  States  is,  however,  small.1  The 
value  depends  somewhat  upon  the  uses  to  which  it  is  to  be  applied. 


1  Mineral  Resources  of  the  United  States,  1892,  p.  178. 


130 


THE  NON-METALLIC  MINERALS. 


Pyrolusite  and  psilomelane  only  are  of  value  in  the  production 
of  chlorine  as  above  noted.  These  are  rated  according  to  their 
percentages  of  peroxide  of  manganese  (MnO2).  The  standard  for 
the  German  ores  is  given  at  57  per  cent  MnO2,  and  70  per  cent 
for  Spanish.  For  the  manufacture  of  spiegeleisen  the  prices  are 
based  on  ores  containing  not  more  than  8  per  cent  silica  and  o.io 
per  cent  phosphorus,  and  are  subject  to  deductions  as  follows: 
For  each  i  per  cent  silica  in  excess  of  8  per  cent,  15  cents  a  ton; 
for  each  0.02  per  cent  phosphorus  in  excess  of  o.io  per  cent,  i  cent 
per  unit  of  manganese.  Settlements  are  based  on  analysis  made 
on  samples  dried  at  212°,  the  percentage  of  moisture  in  samples 
as  taken  being  deducted  from  the  weight.  The  prices  paid  at 
Bessemer,  Pennsylvania,  in  1894,  based  on  these  percentages,  were 
as  below: 


Manganese. 

Prices  per  Unit. 

Iron. 

Manganese 

Ore  containing  above  40  per  cent  ,  ........ 

Cents 
6 
6 
6 
6 

Cents 
28 
27 
26 

25 

Ore  containing  46  to  40  per  cent.  ......... 

Ore  containing  43  to  46  per  cent.  ......... 

Ore  containing  40  to  43  per  cent  

Otherwise  expressed,  the  value  ranges  from  $5  to  $12  a  ton, 
according  to  quality  and  condition  of  the  market. 

The  total  annual  output  of  mines  in  the  United  States  is  but 
some  5,000  to  6,000  tons.  This  because  with  the  exception  of  those 
at  Crimora,  Virginia,  the  deposits  are  of  low  grade  or  small  in  size. 

It  is  probable  that  the  total  consumption  in  pottery  and  glass 
manufacture  does  not  exceed  500  tons  a  year,  of  which  about  two- 
thirds  are  used  in  glass  making.  The  amount  used  in  bromine  manu- 
facture and  the  other  purposes  enumerated  probably  amounts  to 
another  500  tons.  The  remainder  is  used  in  connection  with  iron  and 
steel  manufacture,  chiefly  in  the  production  of  steel  and  a  pig  iron 
containing  considerable  manganese  for  use  in  cast-iron  car  wheels. 
In  the  crucible  process  of  steel  manufacture  manganese  is  charged 
into  the  pots,  either  as  an  ore  at  the  time  of  charging  the  pots,  or  it 


OXIDES.  131 

is  added  as  spiegeleisen  or  ferromanganese  at  the  time  of  charging 
or  during  the  melting,  usually  toward  the  close  of  the  melting,  so 
as  to  prevent  too  great  a  loss  of  manganese  by  oxidation.  In  the 
Bessemer  and  open-hearth  process  the  manganese  is  added  as  spiegel- 
eisen or  ferromanganese  at  or  near  the  close  of  the  process,  just 
before  the  casting  of  the  metal  into  ingots. 

It  has  been  found  in  recent  years  that  a  chilled  cast- iron  car 
wheel  containing  a  percentage  of  manganese  is  much  tougher, 
stronger,  and  wears  better  than  when  manganese  is  absent.  For 
this  reason  large  amounts  of  manganiferous  iron  ores  are  used  in 
the  manufacture  of  Lake  Superior  pig  iron  intended  for  casting 
into  chilled  cast-iron  car  wheels.  (See  also  The  Mineral  Industry, 
VIII  1899.) 

II        MINERAL   WATERS. 

From  a  strictly  scientific  standpoint  any  water  is  a  mineral  water, 
since  water  is  itself  a  mineral — an  oxide  of  hydrogen.  Common 
usage  has,  however,  tended  toward  the  restriction  of  the  name  to 
such  waters  as  carry  in  solution  an  appreciable  quantity  of  other 
mineral  matter  although  the  actual  amounts  may  be  extremely 
variable. 

Of  the  various  salts  held  in  solution,  those  of  sodium,  calcium, 
and  iron  are  the  more  common,  and  more  rarely,  or  at  least  in 
smaller  amounts,  occur  those  of  potassium,  lithium,  magnesium, 
strontium,  silicon,  etc.  The  most  common  of  the  acids  is  carbonic, 
and  the  next  probably  sulphuric. 

Classification. — The  classification  of  mineral  water  is  a  matter 
attended  with  great  difficulty  from  whatever  standpoint  it  is  ap- 
proached. Such  classification  may  be  either  geographic,  geologic, 
therapeutic,  or  chemical,  though  the  first  two  are  naturally  of  little 
value,  and  the  therapeutic,  with  our  present  knowledge,  is  a  prac- 
tical impossibility.  The  chemical  classification  is,  on  the  whole, 
preferable,  although  even  this,  owing  to  the  great  variation  of  methods 
of  stating  results  used  by  analytical  chemists,  is  at  present  attended 
with  some  difficulty.  Dr.  A.  C.  Peale,  the  well-known  authority 
on  American  mineral  waters,  has  suggested  the  scheme  given  below,1 

1  Annual  Report  of  the  United  States  Geological  Survey,  1892-93,  p.  64. 


132  THE  NON-METALLIC  MINERALS. 

and  from  his  writings  has  been  gleaned  a  majority  of  the  facts  here 
given. 

According  to  their  temperatures  as  they  flow  from  the  springs 
the  waters  are  divided  primarily  into  (A)  thermal  and  (B)  non-  thermal, 
a  thermal  water  being  one  the  mean  annual  temperature  of  which  is 
70°  F.  or  above.  Each  of  these  groups  is  again  subdivided  according 
to  the  character  of  the  acids  and  their  salts  held  in  solution  as  below: 

Class      I.  Alkaline. 

Class    II.Alkaline-saUne.{^teed. 


OassHLSaEne 


f  Sulphated. 

Cla**  TV     Arid  J  Muriated- 

Class  IV.   Acid  .........  j  ,  Su,  hated 

LSl]    eous  1  Muriated. 

Any  spring  of  water  may  be  characterized  by  the  presence  or 
absence  of  gas  when  it  is  designated  by  one  of  the  following  terms: 
(i)  Non-gaseous  (free  from  gas).  (2)  Carbonated  (containing  car- 
bonic-acid gas).  (3)  Sulphureted  (containing  hydrogen  sulphide). 
(4)  Azotized  (containing  nitrogen  gas).  (5)  Carbureted  (having 
carbureted  hydrogen). 

In  cases  where  there  is  a  combination  of  gases  such  is  indicated 
by  a  combination  of  terms,  as  sulphocarbonated,  etc.  The  classes 
may  be  further  subdivided  according  to  the  predominating  salt  in 
solution,  as  (i)  sodic,  (2)  lithic,  (3)  potassic,  (4)  calcic,  (5)  magnesic* 
(6)  chalybeate,  (7)  aluminous. 

The  alkaline  waters,  Class  I  above,  include  those  which  are 
characterized  by  the  presence  of  alkaline  carbonates.  Generally  such 
are  characterized  also  by  the  presence  of  free  carbonic  acid.  Nearly 
one-half  the  alkaline  springs  of  the  United  States  are  calcic-alkaline, 
that  is,  carry  calcium  carbonate  as  the  principal  constituent.  The 
saline  waters  include  those  in  which  sulphates  or  chlorides  predomi- 
nate. They  are  more  numerous  than  are  the  alkaline  waters.  The 
alkali-saline  class  includes  all  waters  in  which  there  is  a  combination 
of  alkaline  carbonates  with  sulphates  and  chlorides;  the  acid  class 
includes  all  those  containing  free  acid,  which  is  mainly  carbonic, 
though  it  may  be  silicic,  muriatic,  or  sulphuric. 

The  character  of  the  salts  held  in  solution  is  the  same  for  both 


OXIDES.  133 

thermal  and  non- thermal  springs,  thoug  i  as  a  general  rule  the  amount 
of  salt  is  greatest  in  those  which  are  classed  as  thermal.  Thus  at 
the  Hot  Springs  of  Virginia  one  of  the  springs,  with  a  temperature  of 
78°  F.,  has  18.09  grains  to  the  gallon  of  solid  contents,  while  another, 
with  a  temperature  of  110°  F.,  has  33.36  grains  to  the  gallon. 

Source  of  mineral  waters. — Pure  water  is  an  universal  solvent  and 
its  natural  solvent  power  is  increased  through  the  carbonic  acid 
which  it  takes  up  in  its  passage  through  the  atmosphere,  and  by  this 
same  acid  and  other  organic  and  inorganic  acids  or  alkalies  which 
it  acquires  in  passing  through  the  soil  and  rocks.  The  water 
of  all  springs  is  meteoric,  that  is,  it  is  water  which  has  fallen  upon 
the  earth  from  clouds,  and  gradually  percolating  downward  issues 
again  in  the  form  of  springs  at  lower  levels.  In  this  passage  through 
the  superficial  portion  of  the  earth's  crust  it  dissolves  the  various 
salts,  the  kind  and  quantity  being  dependent  upon  the  kind  of 
rocks,  the  temperatures  and  pressure  of  the  water,  as  well  as  the 
amount  of  absorbed  gases  it  contains. 

Both  the  mineral  contents  and  the  temperature  of  spring  waters 
are  dependent  upon  the  geological  features  of  the  country  they 
occupy.  As  a  rule  springs  in  regions  of  sedimentary  rocks  carry  a 
larger  proportion  of  salts  than  those  in  regions  of  eruptive  and  meta- 
morphic  rocks.  Thermal  springs  are  limited  to  regions  of  com- 
parative recent  volcanic  activity,  or  where  the  rocks  have  been 
disturbed,  crushed,  folded,  and  faulted,  as  in  mountainous  regions. 
Occasional  thermal  springs  are  met  with  in  undisturbed  areas,  but 
such  are  regarded  as  of  deep-seated  origin,  and  to  owe  their  tempera- 
tures to  the  great  depths  from  which  they  are  derived. 

Distribution. — Mineral  springs  of  some  sort  are  to  be  found  in 
each  and  all  of  the  States  of  the  American  Union,  though  naturally 
the  resources  of  the  more  sparsely  settled  States  have  not  as  yet  been 
fully  developed.  For  this  reason  the  table  given  on  page  134  is  to 
a  certain  extent  misleading. 

Uses. — The  mineral  waters  are  utilized  mainly  for  drinking  and 
bathing  purposes,  the  thermal  springs  being  naturally  best  suited  for 
bathing,  and  the  non-thermal  for  drinking  purposes. 


134 


THE  NON-METALLIC  MINERALS. 


PRODUCTION  OF  MINERAL  WATERS  IN   1899  BY  STATES  AND  TERRITORIES. 


1908. 

State  or  Territory. 

Springs 
Report- 
ing. 

Quantity 

Sold 
(gallons). 

Value. 

Alabama  

8 

00  IQ2 

$31,  ^83 

Arkansas 

IO 

I    I7C.  OC.  3 

229  260 

California  

40 

1,060,770 

400,872 

Colorado 

1  1 

761  ic.o 

127  7  2O 

Connecticut 

I  c 

424  826 

36  4O4 

Florida 

I  2 

123  C.  C.  2 

20  >6o 

Georgia  .  .            .  .                  .    . 

14 

346  1  08 

C.O  O3O 

Illinois  

17 

68c,  763 

c8  QO4 

Indiana  

1C 

6lC  42Q 

CQO  8?0 

Iowa  

i 

403,^,00 

r  r   -3  CQ 

Kansas  

16 

370,043 

74  380 

Kentucky  

12 

707,186 

66,112 

Louisiana  

? 

400,500 

52,020 

Mxiine 

27 

I   182  3  22 

3O4  346 

Maryland 

g 

806  673 

7s  8<;8 

^Massachusetts 

61 

43QC.  O4O 

227  OO7 

Michigan 

24 

2  OO4  433 

88  910 

Minnesota 

1  I 

10  o8c,  c  76 

eci  086 

Mississippi 

8 

2C7  2OO 

c  2  78o 

Missouri                  .    .        

30 

682  821 

86  043 

Nebraska         .        

-3 

48  408 

1  1  O47 

New  Hampshire     

Q 

83<C  340 

2C,Q  C,2O 

New  Jersey     

I? 

I  100,023 

JJ'J 
126,603 

New  Mexico  

6 

152,200 

l6,o6o 

New  York  

47 

8,OO7,OQ2 

877,648 

North  Carolina 

18 

1  60  19? 

27  163 

Ohio 

27 

2  4OQ  ^08 

I  24  O38 

Oklahoma 

c  -24.  1  14 

c  2  77Q 

Oregon 

6 

2C.    7C.O 

8  830 

Pennsylvania 

32 

I  43O  480 

IQ7  4O7 

Rhode  Island                     

o 

tfQ4  208 

30  4O? 

South  Carolina                        

13 

2?I   <72 

7O  037 

Tennessee                   

14 

712  QI2 

68  603 

Texas                  

36 

i,q86  634 

I=CI,CU2 

Vermont          

Cf 

107,800 

16,380 

Virginia     

46 

2,009,614 

207,  nc 

Washington  

c 

38,000 

1^,650 

^^est  Virginia 

I3O  2O^ 

7Q   QI  C 

'Wjsconsin                                                         

28 

6  084  ^71 

I  41  3  IO7 

States  or  Territories  of  one  or  two  springs  each  

I   2O2   3IO 

ic?  i?7 

Total               

6(K 

56,108  820 

$7,287,260 

CARBONATES.  135 


V.     CARBONATES. 

I.      CALCIUM    CARBONATE. 

Calcite,  Calc  Spar,  Iceland  Spar.— These  are  the  names  given 
to  the  variety  of  calcium  carbonate  crystallizing  in  the  rhombohedral 
division  of  the  hexagonal  system.  The  mineral  occurs  under  a  great 
variety  of  crystalline  forms,  which  are  often  extremely  perplexing 
to  any  but  an  expert  mineralogist.  The  chief  distinguishing  charac- 
teristics of  the  mineral  are  (i)  its  pronounced  cleavage,  whereby  it 
splits  up  into  rhombohedral  forms,  with  smooth,  lustrous  faces, 
and  (2)  its  doubly  refracting  property,  which  is  such  that  when 
looked  through  in  the  direction  of  either  cleavage  surfaces  it  gives  a 
double  image.  It  is  to  this  property,  accompanied  with  its  trans- 
parency, that  the  mineral,  as  a  crystallized  compound,  owes  its 
chief  value,  though  as  a  constituent  of  the  rock  limestone  it  is  applied 
to  a  great  variety  of  industrial  purposes.  When  not  sufficiently 
transparent  for  observing  its  doubly  refracting  properties  the  mineral 
is  readily  distinguished  by  its  hardness  (3  of  Dana's  scale)  and  its 
easy  solubility,  with  brisk  effervescence,  in  cold  dilute  acid.  This 
last  is  likewise  a  characteristic  of  aragonite,  from  which  it  can  be 
distinguished  by  its  lower  specific  gravity  (2.65  to  2.75)  and  its 
cleavage.  Calcium  carbonate,  owing  to  its  ready  solubility  in 
terrestrial  waters,  is  one  of  the  most  common  and  widely  disseminated 
of  compounds.  Only  the  form  known  as  double  spar,  or  Iceland 
spar,  will  here  be  considered. 

Origin  and  mode  of  occurrence. — Calc  spar  is  invariably  a  second- 
ary mineral  occurring  as  a  deposit  from  solution  in  cracks,  pockets, 
and  crevices  in  rocks  of  all  kinds  and  all  ages.  The  variety  used 
for  optical  purposes  differs  from  the  rhombohedral  cleavage  masses 
found  in  innumerable  localities  only  in  its  transparency  and  freedom 
from  flaws  and  impurities.  The  chief  commercial  source  of  the 
mineral  has  for  many  years  been  Iceland,  whence  has  arisen  the 
term  Iceland  spar,  so  often  applied.  For  the  account  of  the  occur- 
rences of  the  mineral  at  this  locality,  as  given  below,  we  are  indebted 


136  THE  NON-METALLIC  MINERALS. 

mainly  to  Th.  Thoroddsen.1  The  quarry  is  described  as  situated 
on  an  evenly  sloping  mountainside  at  Reydarfjord,  about  100  meters 
above  the  level  of  the  ocean  and  a  little  east  of  the  Helgustadir  farm. 
(See  Plate  XII.) 

The  veins  of  spar  are  in  basalt,  and  at  this  spot  have  been  laid 
bare  through  the  erosive  action  of  a  small  stream  called  the  "  Silfur- 
lakur,"  the  Icelandic  name  of  the  spar  being  "  Silfurberg  "  The 
quarry  opening  is  on  the  western  side  of  this  brook,  and  at  date 
of  writing  was  some  72  feet  long  by  36  feet  wide  (see  Fig.  i  of  plate). 
In  the  bottom  and  sides  of  this  opening  the  calc  spar  is  to  be  seen  in 
the  form  of  numerous  interlocking  veins,  ramifying  through  the  basalt 
in  every  direction  and  of  very  irregular  length  and  width,  the  veins 
pinching  out  or  opening  up  very  abruptly.  In  Fig.  2  of  plate  is 
shown  an  area  of  some  40  square  feet  of  the  basaltic  wall  rock,  illus- 
trating this  feature  of  the  occurrence.  Fig.  3  of  the  same  plate 
shows  the  largest  and  most  conspicuous  vein,  the  smaller  having  been 
omitted  in  the  sketch.  The  high  cliffs  on  the  north  side  of  the 
quarry  are  poorer  in  calc-spar  veins,  the  largest  dipping  underneath 
at  an  angle  of  about  40°. 

A  •  comparatively  small  proportion  of  the  calc  spar  as  found  is 
fit  for  optical  purposes.  That  on  the  immediate  surface  is,  as  a  rule, 
lacking  in  transparency.  Many  of  the  masses,  owing  presumably 
to  the  development  of  incipient  fractures  along  cleavage  lines, 
show  internal,  iridescent,  rainbow  hues;  such  are  known  locally  as 
"  litsteinar"  (lightstones).  Others  are  penetrated  by  fine,  tube-like 
cavities,  either  empty  or  filled  with  clay,  and  still  others  contain 
cavities,  sometimes  sufficiently  large  to  be  visible  to  the  unaided  eye, 
filled  with  water  and  a  moving  bubble.  The  most  desirable  material 
occurs  in  comparatively  small  masses  embedded  in  a  red-gray  clay, 
filling  the  vein-like  interspaces  in  the  bottom  of  the  pit.  The  non- 
tiansparent  variety,  always  greatly  in  excess,  occurs  in  cleavable 
masses  and  imperfectly  developed  rhombohedral,  sometimes  i  to  2 
feet  in  diameter,  associated  with  stilbite. 

Calc  spar  has  been  exported  in  small  quantities  from  Iceland 
since  the  middle  of  the  seventeenth  century,  though  the  business 

1Geologiska  Foreningens  I,  Stockholm  Forhandlingar,  XII,  1890,  pp.  247-254. 


PLATE    XII. 

Views  Showing  Occurrence  of  Calcile  in  Iceland. 
[After  Thorroddsen.] 

{Facing  page 


CARBONATES.  13? 

was  not  conducted  with  any  degree  of  regularity  before  the  middle 
of  the  nineteenth  century,  prior  to  that  time  every  one  taking  what  he 
liked  or  could  obtain,  asking  no  one's  permission.  About  the  time 
Bartholin  discovered  the  valuable  optical  properties  of  the  mineral 
(in  1669),  the  royal  parliament  under  Frederick  III  granted  the 
necessary  permission  for  its  extraction.1  It  was  not,  however,  until 
1850  that  systematic  work  was  begun,  when  a  merchant  by  the 
name  of  T.  F.  Thomsen,  at  Seydisfjord,  obtained  permission  of  the 
owner  of  some  three-fourths  of  the  property  (the  pastor  Th.  Erlends- 
son)  to  work  the  same.  The  quarried  material  was  then  transported 
on  horseback  to  the  Northfjord,  and  thence  to  Seydisfjord  by  water. 
In  1854  the  factor  H.  H.  Svendsen,  from  Eskifjord,  leased  the  pastor's 
three- fourths'  right  for  10  rigsdalers  a  year,  and  the  remaining  fourth, 
belonging  to  the  Government,  for  5  rigsdalers.  Svendsen  worked  the 
mine  successfully  up  to  1862,  when  one  Tullinius,  at  Eskifjord,  pur- 
chased the  pastor's  three-fourths  and  leased  the  Government's  share 
for  five  years,  paying  therefor  the  sum  of  100  rigsdalers  (about  $14 
or  $15).  This  lease  was  renewed  for  four  years  longer  at  the  rate 
of  5  rigsdalers  per  year,  and  for  the  year  1872  at  the  rate  of  100 
rigsdalers,  when  the  entire  property  passed  into  the  hands  of  the 
Government  in  consideration  of  the  payment  of  16,000  kroner  (about 
$3,800).  From  that  time  until  1882  the  mine  remained  idle,  when 
operations  were  once  more  renewed,  though  not  on  an  extensive 
scale,  owing,  presumably  in  part,  to  the  fact  that  Tullinius,  the 
last  year  he  rented  the  mine,  had  taken  out  a  sufficient  quantity  to 
meet  all  the  needs  of  the  market.  Over  300  tons  of  the  ordinary 
type  of  the  spar  is  stated  to  have  been  sent  to  England  and  sold  to 
manufacturers  at  about  30  kroner  a  ton,  though  to  what  use  it  was 
put  is  not  stated. 

M.  Lebonne  describes  2  ramifications  of  the  calcite  veins  into  the 
neighboring  rock,  which  have  never  been  worked,  and  it  is  suggested 
that  their  exploitation  might  result  in  an  increased  output. 

1  Laws  of  Iceland,  I,  1668,  pp.  321,  322. 

2  Comptes  Rendus,  Vol.  V,  1887,  p.  1144. 


I38  THE  NON-METALLIC  MINERALS. 

The  workings  have  not  been  carried  to  a  sufficient  depth  to  fully 
indicate  the  extent  of  the  deposit.  For  the  most  part  the  calcite  is 
rendered  semiopaque  by  minute  cracks  following  the  gliding  and 
cleavage  planes,  and  apparently  produced  by  pressure. 

Aside  from  the  locality  at  Helgustadir,  calc  spar  in  quantity 
and  quality  for  optical  purposes  is  known  to  occur  only  at  Djupi- 
fjord,  in  West  Iceland. 

Limestones.— Any  rock  composed  essentially  of  carbonate  of 
lime  is  commonly  designated  a  limestone.  Pure  limestone  is  a 
compound  of  calcium  oxide  and  carbonic  acid  in  the  proportion 
of  56  parts  of  lime  (CaO)  to  44  parts  of  the  acid  (CO2).  In  its 
crystalline  form,  as  exemplified  in  some  of  our  white  marbles,  the 
rock  is  therefore  but  an  aggregate  of  imperfectly  developed  calcite 
crystals,  or,  otherwise  expressed,  is  a  crystalline  granular  aggregate 
of  calcite.  In  this  form  the  rock  is  white  or  colorless,  sufficiently 
soft  to  be  cut  with  a  knife,  and  dissolves  with  brisk  effervescence 
when  treated  with  dilute  hydrochloric  or  nitric  acid. 

As  a  constituent  of  the  earth's  crust,  however,  absolutely  pure 
limestone  is  practically  unknown,  all  being  contaminated  with  more 
or  less  foreign  material,  either  in  the  form  of  chemically  combined 
or  mechanically  admixed  impurities.  Of  the  chemically  combined 
impurities  the  most  common  is  magnesia  (MgO),  which  replaces 
the  lime  (CaO)  in  all  proportions  up  to  21.7  per  cent,  when  the  rock 
becomes  a  dolomite.  This  in  its  pure  state  can  readily  be  distin- 
guished from  limestone  by  its  greater  hardness  and  in  its  not  effer- 
vescing when  treated  with  cold  dilute  acid.  It  dissolves  with  effer- 
vescence in  hot  acids,  as  does  limestone.  As  above  noted,  all  stages 
of  replacement  exist,  the  name  magnesian  or  dolomitic  limestone 
being  applied  to  those  in  which  the  magnesia  exists  in  smaller  pro- 
portions than  that  above  given  (21.7  per  cent).  Iron  in  the  form 
of  protoxide  (FeO)  may  also  replace  a  part  of  the  lime.  Of  the 
mechanically  admixed  impurities  silica  in  the  form  of  quartz  sand 
or  various  more  or  less  decomposed  silicate  minerals,  clayey  and 
carbonaceous  matter,  together  with  iron  oxides,  are  the  more  abun- 
dant. These  exist  in  all  proportions,  giving  rise  to  what  are  known 
as  siliceous,  aluminous,  or  clayey,  carbonaceous,  and  ferruginous 
limestones.  Phosphatic  material  may  exist  in  varying  proportions, 


FIG.  i. — Limestone  Quarry,  Rockland,  Main«. 
[From  photograph  by  E.  S.  Bastin,  U.  S.  Geological  Survey 


FIG.  2. — Limestone  Quarry,  Oglesby,  Illinois. 
From  a  photograph  by  E.  C.  Eckel,  U.  S.  Geological  Survey.] 
PLATE   XIII. 

[Facing  page  138.] 


CARBONATES.  139 

forming  gradations  from  phosphatic  limestones  to  true  phos- 
phates. 

Limestones  are  sedimentary  rocks  formed  mainly  through  the 
deposition  of  calcareous  sediments  on  sea  bottoms;  many  beds, 
however,  as  the  oolitic  limestones,  show  unmistakable  evidences  of 
true  chemical  precipitation.  They  are  in  all  cases  eminently  strati- 
fied rocks,  though  the  evidences  of  stratification  may  not  be  evident 
in  the  small  specimen  exhibited  in  museum  collections.  Varietal 
names  other  than  those  mentioned  above  are  given,  and  which  are 
dependent  upon  structural  features,  adaptability  to  certain  uses,  or 
other  peculiarities.  A  shaly  limestone  is  one  partaking  of  the  nature 
of  shale.  Chalk  is  a  fine  pulverulent  limestone  composed  of  shells 
in  a  finely  comminuted  condition  and  very  many  minute  foramin- 
ifera,  as  elsewhere  noted.  The  name  chalky  limestone  is  frequently 
given  to  an  earthy  limestone  resembling  chalk.  Marl  is  an  impure 
earthy  form,  often  containing  many  shells,  hence  called  shell  marl. 
An  oolitic  limestone  is  one  made  up  of  small  rounded  pellets  like 
the  roe  of  a  fish;  a  hydraulic  limestone  one  suited  to  the  manufac- 
ture of  hydraulic  cement,  and  so  on.  The  name  marble  is  given 
to  any  calcareous  or  even  serpentinous  rock  possessing  sufficient 
beauty  to  be  utilized  for  ornamental  purposes. 

Uses. — Aside  from  their  uses  as  building  materials  as  described 
elsewhere,1  limestones  are  utilized  for  a  considerable  variety  of 
purposes,  the  most  important  being  that  of  fluxes  and  the  manu- 
facture of  mortars  and  cements.  Their  adapatility  to  the  last  men- 
tioned purposes  is  due  to  the  fact  that  when  heated  to  a  temperature 
of  i, 000°  F.  they  lose  their  carbonic  acid,  becoming  converted  into 
anhydrous  calcium  oxide  (CaO),  or  quicklime,  as  it  is  popularly 
called;  and  further,  that  this  quicklime  when  brought  in  contact 
with  water  and  atmospheric  air  greedily  combines  with,  first,  the 
water,  forming  hydrous  calcium  oxide  (CaOH2O),  and  on  drying 
once  more,  with  the  carbonic  acid  of  the  air,  forming  a  more  or  le  s 
hydrated  calcium  carbonate.  In  the  process  of  combining  with 
water  the  burnt  lime  (CaO)  gives  off  a  large  amount  of  heat,  swells 
to  nearly  twice  its  former  bulk,  and  falls  away  to  a  loose,  white 

1  See  Stones  for  Building  and  Decoration.     Wiley  &  Sons,  New  York. 


140  THE  NON-METALLIC  MINERALS. 

powder.  This  when  mixed  with  siliceous  sand  forms  the  common 
mortar  of  the  bricklayers,  or,  if  with  sand  and  hair,  the  plaster  for 
the  interior  walls  of  houses.  Quicklime  formed  from  fairly  pure 
calcium  carbonate  sets  or  hardens  after  but  a  few  days'  exposure, 
the  induration,  it  is  stated,  being  due  in  part  to  crystallization.  The 
less  pure  forms  of  limestone,  notably  those  which  contain  upwards 
of  10  per  cent  of  aluminous  silicates  (clayey  matter),  furnish,  when 
burned,  a  lime  which  slakes  much  more  slowly — so  slowly,  in  fact, 
that  it  is  not  infrequently  necessary  to  crush  it  to  powder  after  burn- 
ing. The  same  limes  when  slaked  are  further  differentiated  from 
those  already  described  by  their  property  of  setting  (as  the  process 
of  induration  is  called)  under  water.  Hence  they  are  known  as 
hydraulic  limes  or  cements,  and  the  rocks  from  which  they  are  made 
as  hydraulic  limestones.  Their  property  of  induration  out  of  con- 
tact with  the  air  is  assumed  to  be  due  to  the  formation  of  calcium 
and  aluminum  silicates.1  Inasmuch  as  these  silicates  are  practically 
insoluble  in  water,  it  follows  that  quite  aside  from  their  greater 
strength  and  tenacity  they  are  also  more  durable;  indeed  there  seems 
no  practical  limit  to  the  endurance  of  a  good  hydraulic  cement,  its 
hardness  increasing  almost  constantly  with  its  antiquity.  Certain 
stones  contain  the  desired  admixtures  of  lime  and  clayey  matter  in 
just  the  right  proportion  for  making  hydraulic  cement,  and  are 
known  as  natural  cement  rock.  In  the  majority  of  cases,  however, 
it  has  been  found  that  a  higher  grade,  stronger  and  more  enduring 
material,  can  be  made  by  mixing  in  definite  proportions,  determined 
by  experiment,  the  necessary  constituents  obtained,  it  may  be,  from 
widely  separated  localities.  As  noted  above  magnesia  is  a  common 
constituent  of  limestone  and  from  the  present  standpoint  it  may  be 
considered  as  an  impurity.  In  the  natural  cements,  however,  the 
presence  of  an  amount  under  20  per  cent  is  not  considered  as  detri- 
mental, provided  the  alumina  and  silica  are  present  in  sufficient 

1  As  assumption  yet  awaiting  proof.  Eckel,  however,  gives  this  assumed  silicate 
in  Portland  cement,  as  having  the  approximate  formula  3CaO,SiO2,  which  corre- 
sponds to  the  proportion  of  73.6  per  cent  CaO  and  26.4  per  cent  SiO2.  As  a  matter 
of  fact,  however,  analyses  of  cements  show  invariably  the  presence  of  more  or  less 
alumina,  and  if  such  silicates  are  actually  formed  they  must  be  of  a  more  complex 
nature,  and  it  is  possible  the  mixture  would  be  best  represented  by  the  formula 
2(3CaOSiO2).y  (2CaOAl2O3). 


CARBONATES.  141 

proportions.  A  higher  temperature  is,  however,  necessary  for  burn- 
ing than  with  the  pure  lime  carbonate.  In  the  making  of  the  artifi- 
cial admixture  the  presence  of  magnesia  in  amounts  exceeding  5 
per  cent  is  considered  undesirable. 

The  exact  relationship  existing  between  composition  and  adaptabil- 
ity to  lime-making  does  not  seem  as  yet  to  be  fully  worked  out.  As 
is  well  known,  the  pure  while  crystalline  varieties  yield  a  quicklime 
inferior  to  the  softer  blue-gray,  less  metamorphosed  varieties.  Never- 
theless, there  are  certain  distinctive  qualities,  due  to  the  presence  and 
character  of  impurities,  which  led  Gen.  Q.  A.  Gillmore  to  adopt  the 
following  classification : 

(1)  The  common  or  fat  limes,  containing,  as  a  rule,  less  than  10  per 

cent  of  impurities. 

(2)  The  poor  or  meagre  limes,  containing  free  silica  (sand)  and  other 

impurities  in  amounts  varying  between   10  per  cent  and  25 
per  cent. 

(3)  The  hydraulic  limes,  which  contain  from  30  to  35  per  cent  of 

various  impurities. 

(4)  The  hydraulic   cements,   which  may   contain  as   much  as   60 

per  cent  of  impurities  of  various  kinds. 

Most  cements  are  manufactured  from  artificial  admixtures  of 
materials,  and  their  considerations  belong,  therefore,  rnore  properly 
to  technology.  Nevertheless  it  has  been  thought  worth  the  while 
here  to  give  in  brief  the  matter  below  relative  to  a  few  of  the  more 
important  and  well-known  varieties  now  manufactured. 

Portland  Cement. — This  takes  its  name  from  a  resemblance 
of  the  hardened  material  to  the  well-known  limestone  of  the 
island  of  Portland  in  the  English  Channel.  As  originally  made  on  the 
banks  of  the  Thames  and  Medway,  it  consists  of  admixtures  of  chalk 
and  clay  dredged  from  the  river  bottoms,  in  the  proportions  of  three 
volumes  of  the  former  to  one  of  the  latter,  though  these  proportions 
may  vary  according  to  the  purity  of  the  chalk.  These  materials  are 
mixed  with  water,  compressed  into  cakes,  dried  and  calcined,  after 
which  it  is  ground  to  a  fine  powder  and  is  ready  for  use.  The 
following  analyses  from  Heath's  Manual  of  Lime  and  Cement  will 


142 


THE  NON-METALLIC  MINERALS. 


serve  to  show  the  varying  composition  of  the  chalk  and  clay  from  the 
English  deposits: 


Constituents. 

Upper  chalk. 

Gray  chalk. 

Clay. 

Calcium  carbonate 

97.90  to  98.60 
.66           1.59 

.10                   .21 

•35             -74 

87-35   to 

1.67 

.10 

•38 

1.14 
.42 

96.52 

6.84 

•5° 
.46 

•93 
4.29 

f  55  to  70 

3       T5 
ii       24 

3         4 
4         8 

I             2 

4         5 

Silica 

^Magnesium  carbonate 

Iron  oxide 

Alumina 

Potash  and  soda         .          . 

Lime                              •      .  .        ... 

^Magnesia                                    .    . 

Carbonic  acid 

It  is  stated  that  the  presence  of  more  than  very  small  quantities 
of  sand,  iron  oxides,  or  vegetable  matter  in  the  clay  is  detrimental. 
A  good  cement  mud  before  burning  may  contain  from  68  to  78 
per  cent  of  calcium  carbonate,  21  to  15  per  cent  of  silica,  and  from 
10  to  7  per  cent  of  alumina. 

The  following  analyses  from  the  same  source  as  the  above  serve 
to  show  (I)  the  composition  of  the  clay;  (II)  the  mixed  clay  and 
ch&lk  or  "slurry,"  as  it  is  called,  and  (III)  the  cement  powder  pre- 
pared from  the  same: 


Constituents. 

Cfa'y. 

II. 

Slurry. 

III. 
Cement. 

62.13 

2.13 

Calcium  carbonate 

2  oi 

60  O7 

Silica  (soluble) 

CA    IA 

1  1  77 

2O  dC 

Alumina 

14  68 

A    Af 

8  os 

^Magnesium  carbonate  

A   48 

2  8? 

IVtagnesia    ...... 

i  d.8 

Iron  oxide                                    . 

7    76 

213 

437 

Sand       ....              

87 

I  24. 

08 

Water  

I  ^.03 

7  ^0 

Eckel  defines  *  a  Portland  cement,  as  the  term  is  now  commercially 
used,  as  the  product  obtained  by  finely  pulverizing  a  clinker  formed 
by  burning  to  semifusion  an  intimate  artificial  mixture  of  finely 
ground  calcareous  and  argillaceous  material,  consisting  approx- 


1  Cements,  Limes  and  Plasters.     Wiley  &  Sons,  New  York. 


CARBONATES. 


imately  of  three  parts  of  lime  carbonate  to  one  part  of  silica,  alumina 
and  iron  oxide.  The  ratio  of  lime  (CaO)  in  the  finished  product, 
to  all  other  constituents  named,  should  not  be  less  than  1.6  to  i,  or 
more  than  2.3  to  i. 

Several  brands  of  Portland  cement  are  now  manufactured  in 
America  on  the  above  basis,  the  proportions  having  been  worked 
out  by  experiment.  At  the  Coplay  Cement  Works,  in  Lehigh  County, 
Pennsylvania,  a  blue-gray  crystalline  limestone  and  dark-gray  more 
siliceous  variety  are  ground  and  mixed  into  the  desired  proportions, 
molded  into  a  brick,  and  burnt  to  the  condition  of  a  slag.  The 
material  is  then  ground  to  a  powder  and  forms  the  cement. 

The  chemical  composition  of  the  samples  as  given  are  as  follows : 


Constituents. 

Limestone. 

Cement 
rock. 

Compound 
of 
the  two. 

Clinker. 

Silica  (SiO  )                    

2.IO 

I  ^.22 

I  3  22 

22  74 

Alumina  (Al  O»)  ....        .......... 

) 

Iron  Oxide  (Fe2O3)  

\             .84 

4.24 

5.20 

10.50 

Calcium  carbonate  (CaCO,)  .   . 

06  17 

6088 

77  OO 

CaO  61  82 

Magnesian  Carbonate  (MgCO3)  .  .  . 

Trace. 

4.60 

4-2O 

MgO  2.05 

An  impure  limestone,  forming  a  portion  of  the  water-lime  group 
of  the  Upper  Silurian  formations  at  Buffalo,  New  York,  forms  a 
"natural  cement"  rock  which  is  utilized  in  the  manufacture  of  the 
so-called  Buffalo  Portland  Cement.1 

The  so-called  Rosendale  cement  is  made  from  the  Tentaculite  or 
Water  Limestone  of  the  lower  Helderberg  group  as  developed  in 
the  township  of  Rosendale,  Ulster  County,  New  York.  According 
to  Darton2  there  are  two  cement  beds  in  the  Rosendale- Whiteport 
region,  at  Rosendale  the  lower  bed  or  dark  cement  averaging  some 
21  feet  in  thickness  and  the  upper  or  light  cement  n  feet,  with  14 
to  15  feet  of  water- lime  intervening.  In  the  region  just  south  of 
Whiteport  the  upper  white  cement  beds  have  a  thickness  of  12  feet 
and  the  lower  or  gray  cement  of  18  feet,  with  19  to  20  feet  of  water- 
lime  beds  between  them.  The  underlying  formation  is  quartzite. 


1  Cement  Rock  and  Gypsum  Deposits  in  Buffalo.     J.  Pohlman. 
the  American  Institute  of  Mining  Engineers,  XVII,  1889,  p.  250. 

2  Report  of  the  State  Geologist  of  New  York,  I,  1893. 


Transactions  of 


144 


THE  NON-METALLIC  MINERALS 


The  method  of  mining  the  material  from  .the  two  beds,  as  well  as 
their  inclination  to  the  horizon,  is  shown  in  Plate  XIV. 

Roman  Cement. — The  original  Roman  cement  appears  to  have 
been  made  from  an  admixture  of  volcanic  ash  or  sand  (pozzuolana, 
peperino,  trass,  etc.)  and  lime,  the  proportions  varying  almost 
indefinitely  according  to  the  character  of  the  ash.  The  English 
Roman  cement  is  made  by  calcining  septarian  nodules  dredged  up 
from  the  bottoms  of  Chichester  Harbor  and  off  the  coast  of  Hamp- 
shire, and  from  similar  nodules  obtained  from  the  Whitby  shale 
beds  of  the  Lias  formations  in  Yorkshire  and  elsewhere.  The 
following  analysis  of  the  cement  stone  from  Sheppey,  near  South 
End,  will  serve  to  show  the  character  of  the  material: 


Constituents. 

Carbonate  of  lime 

64.  oo 

Silica 

17    7^ 

Alumina         

6    7«J 

Magnesia       

O    CO 

Oxide  of  iron  

w«5« 

6  oo 

Oxide  of  manganese 

I    OO 

Water 

300 

Loss  

I    OO 

IOO.OO 

The  names  concrete  and  beton  are  applied  to  admixtures  of  mor- 
tar, hydraulic  or  otherwise,  and  such  coarse  materials  as  sand, 
gravel,  fragments  of  shells,  tiles,  bricks,  or  stone.  According  to 
Gillmore  the  matrix  of  the  beton  propor  is  a  hydraulic  cement, 
while  that  of  the  concrete  is  non- hydraulic.  The  terms  are,  however, 
now  used  almost  synonymously. 

Aside  from  their  uses  as  above  indicated  limestones  are  used  in 
the  preparation  of  lime  for  fertilizing  purposes.  For  this  purpose, 
as  before,  the  lime  carbonate  is  reduced  to  the  condition  of  oxide 
by  burning  and  then  allowed  to  become  air-slaked,  when  it  remains 
in  the  condition  of  a  fine  powder  suitable  for  direct  application  to 
the  land  as  is  the  plaster  made  from  gypsum.  A  lime  prepared  by 
burning  oyster  shells  is  utilized  in  a  similar  manner. 


I 


•    ^  tJ 

E  ^  f 

n'  •*" 

0  ~  *j 

1  a  B 

_  cT  < 


08 
8  a 


<  "i 
o  ?r 
•<  • 


CARBONATES.  145 

Finely  ground  raw  limestone  is  sometimes  used  with  good  effect. 
In  regions  favorably  situated,  as  the  salt  regions  of  Michigan,  large 
quantities  of  limestone  are  used  in  the  manufacture  of  soda  ash,  or 
carbonate  of  soda,  which  in  its  turn  is  used  in  the  manufacture  of 
glass.  Limestone  of  a  high  degree  of  purity  is  required  for  this 
purpose. 

The  name  chalk  is  given  to  a  white,  somewhat  loosely  coherent 
variety  of  limestone  composed  of  the  finely  comminuted  shells  of 
marine  mollusks,  among  which  microscopic  forms  known  as 
foraminifera  are  abundant.  The  older  text-books  gave  one  to 
understand  that  foraminiferal  remains  constituted  the  main 
mass  of  the  rock,  but  the  researches  of  Sorby l  showed  that 
fully  one-half  the  material  was  finely  comminuted  shallow-water 
forms,  such  as  inoceramus,  pecten,  ostrea,  sponge  spicules,  and 
echinoderms. 

Chalk  belongs  to  the  Cretaceous  era,  occurring  in  beds  of  varying 
thickness,  alternating  with  shales,  sands,  and  clays,  and  often  in- 
cluding numerous  nodules  of  a  dark  chalcedonic  silica  to  which  the 
name  flint  is  given.  Though  a  common  rock  in  many  parts  of  Europe, 
it  is  known  to  American  readers  mainly  by  its  occurrence  in  the 
form  of  high  cliffs  along  the  English  coast,  as  near  Dover.  Until 
within  a  few  years  little  true  chalk  was  known  to  exist  within  the 
limits  of  the  United  States.  According  to  Mr.  R.  T.  Hill2  there  are, 
however,  extensive  beds,  sometimes  500  feet  in  thickness,  extending 
throughout  the  entire  length  of  Texas,  from  the  Red  River  to  the 
Rio  Grande,  and  northward  into  New  Mexico,  Kansas,  and  Arkansas. 
These  chalks  in  many  instances  so  closely  simulate  the  English 
product,  both  in  physical  properties  and  chemical  composition,  as 
to  be  adaptable  to  the  same  economic  purposes.  The  following 
analyses  from  the  report  above  alluded  to  serve  to  show  the  com- 
parative composition: 


1  Address  to  Geological  Society  of  London,  February,  1879. 

2  Annual  Report  of  the  Arkansas  Geological  Survey,  II,  1888. 


146 


THE  NON-METALLIC  MINERALS. 


Lower 

Upper 

White 

White 

Cretaceous 

Cretaceous 

Cliff 

Chalk  of 

Grav 

Constituents. 

Chalk, 

Chalk, 

Chalk, 

Shore- 

Chalk, 

Burnet 

Rocky 

Little 

ham, 

Folkstone, 

County, 
Texas. 

Comfort, 
Arkansas. 

River, 
Arkansas. 

Sussex, 
England. 

England. 

02.42 

88.48 

O4.l8 

08  4O 

O4  OQ 

Carbonate  of  magnesia 

i  ^8 

Trace 

I  37 

08 

Silica  and  insoluble  silicates  

i-59 

9-77 

3-49 

1.  10 

•6L 
3.6l 

Ferric  oxide  and  alumina  

.41 

I.2? 

1.41 

Phosphoric  acid,  alumina,  and  loss 

.42 

Trace. 

Water  

.18 

*"*y 

70 

65 

99.98 

99-5° 

101 

100 

IOO 

Chalk  is  used  as  a  fertilizer,  either  in  its  crude  form  or  burnt,  in 
the  manufacture  of  whiting,  in  the  form  of  hard  lumps  by  carpenters 
and  other  mechanics,  and  in  the  manufacture  of  crayons.  Washed, 
chalk  is  used  to  give  body  to  wall  paper;  as  a  whitewash  for  ceilings; 
as  a  thin  coating  on  wood  designed  for  gilding,  being  for  this  purpose 
mixed  with  glue;  to  vary  the  shades  of  gray  in  water-color  paints, 
and  as  a  polishing  powder  for  metals. 

The  marl  commonly  used  in  cement  work  is  described  by  Eckel  as 
a  fine-grained  friable  limestone  which  has  been  deposited  in  the  beds 
of  existing  or  recently  extinct  lakes.  The  deposition  of  the  lime  may 
have  been  due  simply  to  the  escape  of  the  excess  of  carbonic  acid 
necessary  for  holding  it  in  solution,  or  to  the  abstraction  of  the  car- 
bonic acid  by  plants,  particularly  algae  and  mollusks,  in  the  two 
last  cases  the  remains  of  the  organisms  constituting  an  appreciable 
portion  of  the  material.  The  beds  are  lenticular  or  basin- shaped, 
and  of  relatively  small  size — a  natural  consequence  of  their  mode  of 
origin,  and  limited  largely  to  the  lake  countries  of  glaciated  regions. 

Playing  Marbles. — At  Oberstein  on  the  Nahe,  Saxony,  playing 
marbles  are  made  in  great  quantities  from 'limestone.  The  stone  is 
broken  into  square  blocks,  each  of  such  size  as  to  make  a  sphere 
the  size  of  the  desired  marble.  These  cubes  are  then  thrown  into 
a  mill  consisting  of  a  flat,  horizontally  revolving  stone  with  numerous 
concentric  grooves  or  furrows  on  its  surface.  A  block  of  oak  of 


CARBONATES.  147 

the  same  diameter  as  the  stone  and  resting  on  the  cubes  is  then 
made  to  revolve  over  them  in  a  current  of  water,  the  cubes  being 
thus  reduced  to  the  spherical  form.  The  process  requires  but  about 
fifteen  minutes. 

Lithographic  Limestone. — For  the  purpose  of  lithography 
there  is  used  a  fine-grained  homogeneous  limestone,  breaking  with 
an  imperfect,  shell-like  or  conchoidal  fracture,  and  as  a  rule  of  a 
gray,  drab,  or  yellowish  color.  A  good  stone  must  be  sufficiently 
porous  to  absorb  the  greasy  compound  which  holds  the  ink  and 
soft  enough  to  work  readily  under  the  engraver's  tool,  yet  not  too 
soft.  It  must  be  uniform  in  texture  throughout  and  be  free  from  all 
veins  and  inequalities  of  any  kind,  in  order  that  the  various  reagents 
used  may  act  upon  all  exposed  parts  alike.  It  is  evident,  therefore, 
that  the  suitability  of  this  stone  for  practical  purposes  depends 
more  upon  its  physical  than  chemical  qualities.  An  actual  test 
of  the  material  by  a  practical  lithographer  is  the  only  test  of  real 
value  for  stones  of  this  nature.  Nevertheless,  the  analyses  given 
on  the  next  page  are  not  without  interest  as  showing  the  variation 
in  composition  even  in  samples  from  the  same  locality. 

Localities. — Stones  possessing  in  a  greater  or  less  degree  the 
proper  qualities  for  lithographic  purposes  have  from  time  to  time 
been  reported  in  various  parts  of  the  United  States;  from  near 
Bath  and  Stony  Stratford,  England;  Ireland;  Department  of  Indre; 
France,  and  also  Silesia,  India,  and  the  British  American  possessions. 
By  far  the  best  stone,  and  indeed  the  only  stone  which  has  as  yet 
been  found  to  satisfactorily  fill  all  the  requirements  of  the  lithog- 
rapher's art,  and  which  is  the  one  in  general  use  to-day  wherever 
the  art  is  practiced,  is  found  at  Solenhofen,  and  Pappenheim,  on  the 
Danube,  in  Bavaria.  These  beds  are  of  Upper  Jurassic  or  Kimmer- 
idgian  Age  and  form  a  mass  some  80  feet  in  thickness,  though  natu- 
rally not  all  portions  are  equally  good  or  adapted  for  the  same  kind 
of  work.  The  stone  varies  both  in  texture  and  color  in  different 
parts  of  the  quarry,  but  the  prevailing  tints  are  yellowish  or  drab. 
In  the  United  States  materials  partaking  of  the  nature  of  lithographic 
stone  have  been  reported  from  Yavapai  County,  Arizona;  Talla- 
dega  County,  Alabama ;  Arkansas;  Lawrence  County,  Indiana;  near 
Thebes  and  Anna,  Illinois;  James  and  Van  Buren  counties,  Iowa; 


148 


THE  NON-METALLIC  MINERALS. 


Canada  (light-blue  gray) 
Canada  (dark  -blue  gray) 

Missouri,  Rails  County 
Overton,  Tennessee  

Solenhofen,  Bavaria  
Kentucky  (light  gray)  . 
Iowa  (blue-gray)  
Missouri  (light  gray)  .  . 

Solenhofen,  Bavaria  .  .  . 
Solenhofen,  Bavaria  (da 
Solenhofen,  Bavaria  (yel 

I 

f 

•        • 

•        • 

i        i        •        • 

1  « 

§§     # 

b         0 
00          00 

4*        0 

^r        oo 

b\      -<r 
to        «vi 

•**J          to         Oo          O^ 
O         to        to         to 

Oo          O         4*         4" 

00        O           00 
VO              O              H 

OO        Oo         ^J 
\O         4^ 

1 

to        to 

H              M 

••*$        <~n 

M                               M 

4*         4>-          to          O 

4»-        Oo          00 

K 

On       -^j 
O         Op 

OO              M 

to         O 

to        Oo        4>-         to 

•^I             10            OO              M 

•^1              M 

Oo         O^          00 
00        ^»         Oo 

O              H 

p 

p     ; 

0         0 

0          0 

M            Oi 

0          00 
M     .  *          0 

b 

V 

O         0 

Oo          00 
on          00 

tO              M             M 

**••-§£ 

Oo        *0\       "M         M 

O           0 

OJ           to 
K>         Oo 

M          QS 

y 

0 

O 

*     : 

H 

O          0 
O         On 

to         to 
0        4^ 

H 

Cx>          CK> 
O\        *<I 

O              W 

M 

O            K> 

H 

4-.          0\        H 
Oo         "^I        On 

o      ^o       o 

Ol 

H              tO 

bo      b 

Oo 

Insoluble 
Silica. 

H              O 

tO          4^- 

H            OO              O 

bo     oo      -U 

Oo          O          O 

O          O 

Oo         to 
to         O 

|f 

O          0 
t         0 

fc     " 

O        Oo 

O 

4* 

M              M 

o      o      o 

OO 
M              0 

Oo          to 
g,        On 

4*        4*        Oo 
H                   On 

OJ          •£ 

f> 

to        to 

bo      bo 

vo         4* 

to         to         to 

On         to         O 

to        to 

bo     vb 

4>.        Cn 

|| 

^  o 

p     Q 

y    O    •      K 
p     p     <<    ? 

n    "r1 

$  % 

I.I 

Authority. 

CARBONATES.  149 

Hardin,  Estelle,  Kenton,  Clinton,  Meade,  Rowan,  Wayne,  and 
Simpson  counties,  Kentucky;  near  Saverton,  Rails  County,  Missouri; 
Clay  and  Overton  counties,  Tennessee;  Burnet  and  San  Saba 
counties,  Texas;  near  Salt  Lake  City,  Utah,  and  at  Fincastle,  Vir- 
ginia. While,  however,  from  nearly,  if  not  quite  every  one  of  these 
localities,  it  was  possible  to  get  small  pieces  which  served  well  for 
trial  purposes,  each  and  every  one  has  failed  as  a  constant  source 
of  supply  of  the  commercial  article,  and  this  for  reasons  mainly  in- 
herent in  the  stone  itself.  It  is  very  possible  that  ignorance  as 
to  proper  methods  of  quarrying  may  have  been  a  cause  of  failure 
in  some  cases. 

The  Arizona  stone  according  to  first  reports  seemed  very  promising. 
Samples  submitted  to  the  writer,  as  well  as  samples  of  work  done  upon 
it,  seemed  all  that  could  be  desired.  It  is  stated  by  Mr.  W.  F. 
Blandy  that  the  quarries  are  situated  on  the  east  slope  of  the  Verdi 
range,  about  2  miles  south  of  Squaw  Peak  and  at  an  elevation  of 
about  1,200  feet  above  the  Verdi  Valley,  40  miles  by  wagon  road  east 
of  Prescott.  Two  quarries  have  thus  far  been  opened  in  the  same 
strata,  about  1,000  feet  apart,  the  one  showing  two  layers  or  beds 
384  feet  in  thickness,  and  the  other  three  beds  3,188  feet  in  thick- 
ness. As  exposed  the  beds,  which  are  of  Carboniferous  Age,  are 
broken  by  nearly  vertical  fissures  into  blocks  rarely  4  or  5  feet  in 
length.  Owing  to  the  massive  form  of  the  beds  and  the  conchoidal 
fracture  the  stone  can  not  be  split  into  thin  slabs,  but  must  be  sawn. 
No  satisfactory  road  yet  exists  for  its  transportation  in  blocks  of 
any  size,  and  such  material  as  has  thus  far  been  produced  is  in  small 
slabs  such  as  can  be  packed  out  on  the  backs  of  animals. 

The  Alabama  stone  as  examined  by  the  writer  is  finely  granular 
and  too  friable  for  satisfactory  work.  Qualitative  tests  showed 
it  to  be  a  siliceous  magnesian  limestone.  It  is,  of  course,  possible 
that  the  single  sample  shown  does  not  fairly  represent  the  product. 
The  Arkansas  deposit  is  situated  in  Township  14°  N.,  R.  15°  W.  of 
the  5th  p.m.,  sections  14,  23,  and  24,  Searcy  County.  The  color  is 
darker  than  that  of  the  Bavarian  stone.  The  reports  of  those  who 
have  tested  it  are  represented  as  being  uniformly  favorable. 

The  Illinois  stone  is  darker,  but  to  judge  from  the  display  made  in 
the  Illinois  building  at  the  World's  Columbian  Exposition,  1893,  is 


15°  THE  NON-METALLIC   MINERALS. 

capable  of  doing  excellent  work  and  can  be  had  in  slabs  of  good 
size. 

The  Indiana  stone  is  harder  than  the  Bavarian,  and  samples 
examined  were  found  not  infrequently  traversed  by  fine,  hard  veins 
of  calcite. 

The  stone  from  Saverton,  Missouri,  is  compact  and  fine  grained, 
with,  however,  fine  streaks  of  calcite  running  through  it.  It  leaves 
only  a  small  brownish  residue  when  dissolved  in  dilute  acid.  This 
stone  has  been  worked  quite  successfully  on  a  small  scale.  The 
State  geologist,  in  writing  on  the  subject,  says : 1  "  Some  of  the 
beds  of  the  St.  Louis  limestone  (Subcarboniferous)  have  been 
successfully  used  for  lithographic  work.  No  bed  is,  however, 
uniformly  of  the  requisite  quality,  and  the  cost  of  selection  of 
available  material  would  seem  to  preclude  the  development  of  an 
industry  for  the  production  of  lithographic  stone." 

From  the  deposit  at  Overton,  Tennessee,  it  is  stated  slabs  40  by 
60  inches  by  3  J  inches  thick  were  obtained,  though  little,  if  anything, 
is  now  being  done.  An  analysis  of  this  stone  is  given  in  the  table. 
Other  promising  finds  are  reported  from  McMinn  County,  in  the 
same  State.  According  to  the  State  geological  reports,  the  stone  lies 
between  two  beds  of  variegated  marble.  The  stratum  is  thought 
to  run  entirely  through  the  county,  but  some  of  the  stone  is  too  hard 
for  lithographic  purposes.  The  best  is  found  8  miles  east  of  Athens 
on  the  farm  of  Robert  Cochrane,  and  a  quarry  has  been  opened  by 
a  Cincinnati  company,  which  pays  a  royalty  of  $250  per  annum. 
It  is  sold  for  nearly  the  same  price  as  the  Bavarian  stone.  It  is  a 
calcareous  and  argillaceous  stone,  formed  of  the  finest  sediment,  of 
uniform  texture,  and  possesses  a  pearl-gray  tint.  The  best  variety 
of  this  stone  has  a  conchoidal  fracture  and  is  free  from  spots  of  all 
kinds. 

In  Meade  County,  Kentucky,  the  stone  furnishing  the  best 
lithographic  material  occurs2  in  a  nearly  horizontal  layer  about  3 
feet  in  thickness.  The  entire  output  is  stated  to  be  "of  good  quality 
for  an  engraving  and  printing  base  for  certain  classes  of  work."  The 

1  Bulletin  No.  3,  Geological  Survey  of  Missouri,  1890,  p.  38. 

2S.  J.  Kubel,  Engineering  and  Mining  Journal,  November  23,  1901,  p.  668. 


CARBONATES.  IS1 

stone  is  of  a  blue-gray  color,  can  be  had  in  large  sizes,  and  is  being 
quite  generally  used  in  the  south  and  southwest,  where  it  is  stated 
to  compare  very  favorably  with  the  imported  Bavarian  material.  The 
quarries  are  operated  by  the  American  Lithographic  Stone  Company, 
located  at  Brandenburg.  In  Rowan  County  the  stone,  according  to 
E.  O.  Ulrich,1  occurs  in  nearly  horizontal  layers  interstratified  with 
yellow  limestone,  arenaceous  oolite,  and  shales  belonging  to  the 
St.  Louis  division  of  the  Subcarboniferous  formations.  The  quarries 
now  developed  lie  east  and  across  the  river  from  the  town  of  Yale. 
The  bed  yielding  lithographic  material  is  some  15  feet  in  thick- 
ness, and  is  overlaid  by  an  equal  thickness  of  stripping.  The 
presence  of  flattened  nodules  of  flint  form  the  chief  drawback  as  the 
quarry  is  at  present  developed.  The  stone  has  been  tested  in  the 
lithographic  department  of  the  U.  S.  Geological  Survey  and  found 
satisfactory. 

A  lithographic  stone  is  described  in  the  State  survey  reports  of 
Texas  as  occurring  at  the  base  of  the  Carboniferous  formations  near 
Sulphur  Springs,  west  of  Lampasas,  on  the  Colorado  River,  and  to 
be  traceable  by  its  outcrops  for  a  distance  of  several  miles,  the  most 
favorable  showing  being  near  San  Saba.  The  texture  of  the  stone 
is  good,  but  as  it  is  filled  with  fine  reticulating  veins  of  calcite,  and  as 
moreover  the  lithographic  layer  itself  is  only  some  6  or  8  inches  in 
thickness,  it  is  obvious  that  little  can  be  expected  from  this  source. 
A  stone  claiming  many  points  of  excellence  has  for  some  years 
been  known  to  exist  in  the  Wasatch  range  within  a  few  miles  of 
Salt  Lake  City,  and  several  companies  are  or  have  been  engaged  in 
its  exploitation. 

Very  encouraging  reports  of  beds  examined  by  men  whose  opin- 
ions should  be  conservative,  come  from  Canadian  sources,  and  it  is 
possible  a  considerable  industry  may  yet  be  here  developed,  though 
little  is  being  done  at  present.  The  descriptions  as  given  in  the 
geological  reports  are  as  follows  :2 

14  The  lithographic  stones  of  the  townships  of  Madoc  and  Mar- 
mora and  of  the  counties  of  Peterboro  and  Bruce  have  been  examined 

Engineering  and  Mining  Journal,  June  28,  1902,  p.  895. 
2  Geology  of  Canada,  1863. 


152  THE   NON-METALLIC  MINERALS. 

and  practically  tested  by  lithographers,  and  in  several  cases  pro- 
nounced of  good  quality;  they  have  also  obtained  medals  at  various 
exhibitions.  They  were  obtained  from  the  surface  in  small  quarries, 
and  possibly  when  the  quarries  are  more  developed  better  stones, 
free  from  'specks'  of  quartz  and  calcite,  will  be  available  in  large 
slabs." 

It  should  be  stated  that  in  actual  use  the  principal  demand  is 
for  stones  some  22  or  28  by  40  inches;  the  largest  ones  practically 
used  are  some  40  by  60  inches  and  3  to  3^  inches  thick.  The  better 
grades  sell  as  high  as  22  cents  a  pound. 

2.    DOLOMITE. 

This  is  a  carbonate  of  calcium  and  magnesium  (Ca,Mg),  CO3,= 
calcium  carbonate,  54.35  per  cent;  magnesium  carbonate  45.65  per 
cent.  Hardness  3.5  to  4;  specific  gravity  2.8  to  2  9;  colors  when 
pure,  white,  but  often  red,  green,  brown,  gray  or  black  fiom  impuri- 
ties. Dolomite,  like  calcite,  occurs  in  massive  beds  or  strata  either 
compact  or  coarsely  crystalline,  and  is  to  the  eye  alone  often  indis- 
tinguishable from  that  mineral.  Like  limestone,  the  dolomites  occur 
in  massive  forms  suitable  for  building  purposes,  or  in  some  cases  as 
marble.  From  the  limestone  they  may  be  distinguished  by  their 
increased  hardness  and  by  being  insoluble  in  cold  dilute  hydrochloric 
acids  The  dolomites,  like  the  limestones,  are  sedimentary  rocks, 
though  it  is  doubtful  if  the  original  sediments  contained  sufficient 
magnesium  carbonate  to  constitute  a  true  dolomite.  They  are 
regarded  rather  as  having  resulted  from  the  alteration  of  limestone 
strata  by  the  replacement  of  a  part  of  the  calcium  carbonate  by 
carbonate  of  magnesium. 

Uses. — Aside  from  its  use  as  a  building  material,  dolomite  has 
of  late  come  into  use  as  a  source  of  magnesia  for  the  manufacture  of 
high  y  refractory  materials  for  the  linings  of  converters  in  the  basic 
processes  of  steel  manufacture.  According  to  a  writer  in  the  Indus- 
trial World1  the  magnesia  is  obtained  by  mixing  the  calcined  dolo- 
mite with  chloride  of  magnesia,  whereby  there  is  formed  a  soluble 

'June  i,  1893. 


CARBONATES. 


153 


calcic  chloride  which  "s  readily  removed  by  solution,  leaving  the 
insoluble  magnesia  behind.  According  to  another  process  the  cal- 
cined dolomite  is  treated  with  dissolved  sugar,  leading  to  the  forma- 
tion of  sugar  of  lime  and  deposition  of  the  magnesia;  the  solution 
of  sugar  of  lime  is  then  exposed  to  carbonic  acid  gas,  which  separates 
the  lime  as  carbonate,  leaving  the  sugar  as  refuse.  Recently  it  has 
been  proposed  to  use  magnesia  as  a  substitute  for  plaster  of  Paris 
for  casts,  etc. 

The  snow-white  coarsely  crystalline  Archean  dolomite  com- 
mercially known  as  snowflake  marble,  and  which  occurs  at  Pleasant- 
ville,  in  Westchester  County,  New  York,  is  finely  ground  and  used 
as  a  source  of  carbonic  acid  in  the  manufacture  of  the  so-called 
soda  and  other  carbonated  waters. 

3.    MAGNESITE. 

This  is  a  carbonate  of  magnesium,  MgCO3,  =  carbon  dioxide, 
52.4  per  cent;  magnesia,  47.6  per  cent.  Usual y  contaminated 
with  carbonates  of  lime,  iron  and  free  silica. 

The  following  analysis  will  serve  to  show  the  average  run  of 
the  material,  both  in  the  crude  state  and  after  calcining: 


Constituents. 

Styria. 

Greece. 

Crude  magnesite. 
Carbonate  of  magnesia 

oo  o  to  06  o 

Carbonate  of  lime 

o  c  to    20 

Carbonate  of  iron 

3.0  to    60 

FeO          o  08 

Silica 

I  O 

O  C2 

M^anganons  oxide  

o  ^ 

"Water       Q  CA 

Burnt  magnesite. 
^Magnesia  

77  6 

82  46  to  CK  36 

Lime  .... 

7-3 

08^  to   IOQ2 

Alumina  and  ferric  oxide 

I  2   O 

o  c6  to     2.  ^4. 

Silica  

I   2 

O  7  2  to     7  08 

The  mineral  occurs  rarely  in  the  form  of  crystals,  but  is  commonly 
in  a  compact,  finely  granular  condition  of  white  or  yellowish  color 
somewhat  resembling  unglazed  porcelain,  and  more  rarely  crystal- 
line granular,  like  limestone  or  dolomite. 


154  THE  NON-METALLIC  MINERALS. 

It  is  hard  (3.5  to  4.5)  and  brittle,  with  a  vitreous  luster,  and  is 
unacted  upon  by  cold,  but  dissolves  with  brisk  effervescence  in  hot 
hydrochloric  acid. 

Origin  and  occurrence.  —  The  mineral  is  nearly,  if  not  quite, 
always  secondary  and,  in  many  cases  at  least,  a  product  of  alter- 
ation of  eruptive  rocks  rich  in  olivine  or  other  iron  magnesian  sili- 
cates. A  theoretical  view  of  this  origin,  as  given  by  various  authori- 
ties, is  shown  in  the  following  formulas: 

3Mg3FeSi2O8    +    3CO2    +    4H2O    +     O      = 

Olivine  Carbon  Water  Oxygen 

dioxide 


i2O9    4-    Fe3O4    +    3MgCO3    +    2SiO2. 

Serpentine  Magnetite  Magnesite  Quartz 

The  beds  in  the  Swiss  Tyrol  are,  however,  regarded  by  M.  Koch  1 
as  due  to  an  alteration  of  limestone  through  the  downward  perco- 
lation of  magnesian  solutions,  a  process  closely  akin  to  the  now 
commonly  accepted  idea  of  dolomization.  The  descriptions  thus 
far  given  regarding  the  Canadian  and  Styrian  deposits,  while  not 
conclusive,  would  seem  to  indicate  that  these  might  also  result  from 
the  alteration  of  beds  of  sedimentary  origin. 

It  naturally  follows  that  magnesite  deposits  originating  through 
the  alteration  of  olivine  rocks  are  commonly  associated  with  ser- 
pentines. Such  occur,  as  a  rule,  in  the  form  of  granular  aggregates 
and  irregular  veins,  some  of  which  are  apparently  mere  shrinkage 
cracks,  as  shown  in  Fig.  2,  Plate  XV.  They  may  vary  from  mere 
threads  to  bed-like  masses  perhaps  20  feet  in  thickness.  It  is  prob- 
able, from  their  mode  of  formation,  that  such  deposits  are  all 
comparatively  shallow,  extending  little,  if  any,  below  the  permanent 
water  level.  This  statement  is,  however,  founded  largely  on  theo- 
retical considerations. 

Localities.  —  Although  a  common  mineral,  magnesite  in  sufficient 
quantities  to  be  commercially  important  is  comparatively  rare.  The 
principal  localities  outside  of  the  United  States,  so  far  as  now  known, 
are  Austria,  Greece,  and  India,  although  the  material  is  reported 

1  Zeit.  deut.  geol.  Gesel.  XLV,  pt.  2   1893. 


FIG.  i. — Quarry  of  Lithographic  Limestone,  Solenhofen,  Bavaria. 
[From  a  photograph.] 


FIG.  2. — Stockwork  of  Magnesite  Veins  in  Serpentine,  near  Winchester,  Riverside 

County,  California. 
[After  F.  L.  Hess,  Bulletin  No.  355,  U.  S.  Geological  Survey.] 

PLATE  XV. 

[Facing  page  154.} 


CARBONATES.  155 

AS  occurring  in  Italy,  Norway,  Russia,  South  Africa,  Australia,  and 
Mexico.  In  the  United  States  the  only  commercially  important 
localities  are  in  California,  though  at  one  time  material  occurring  in 
the  form  of  small  shrinkage  cracks  or  gash  veins  in  the  serpentinous 
depos  Is  of  Lancaster  County,  Pennsylvania,  and  adjacent  parts  of 
Maryland  was  worked  to  a  considerable  extent,  the  material  being 
utilized  in  the  manufacture  of  Epsom  salts. 

Attention  was  first  directed  to  the  California  deposits  by  W.  P. 
Blake.1  These  were  subsequently  inspected  by  H.  G.  Hanks,  the 
State  mineralogist,  and  have  since  been  the  subject  of  a  special 
monograph  by  Mr.  Frank  L.  Hess  2  of  the  United  States  Geological 
Sui  vey. 

According  to  these  various  authorities  the  Californian  deposits 
are  scattered  along  the  coast  range  from  Mendocino  County  as  far 
south  as  Kern  and  Santa  Barbara  counties.  These  are  being  or 
have  been  worked  in  Sonoma,  Santa  Clara,  Tulare  and  Napa  counties. 
In  all  cases  the  material  occurs  in  connection  with  more  or  less 
decomposed  serpentinous  rocks  which  are  themselves  a  product  of 
decomposition  of  igneous  rocks,  of  which  olivine  was  the  prevailing 
constituent. 

Loose  boulders  of  a  peculiar  granular,  almost  saccharoidal  form 
of  magnesite,  looking  much  1  ke  a  crystalline  dolomite,  have  been 
found  for  many  years  in  the  glacial  drift  south  of  Quebec,  and  within 
a  few  years  the  material  has  been  reported  as  having  been  found  in 
place  in  the  township  of  Grenville.  The  outcrops  are  described  as 
being,  in  some  cases,  upwards  of  100  feet  in  width  and  to  have  been 
traced  for  a  distance  of  a  quarter  of  a  mile.  The  material  is,  how- 
ever, by  no  means  pure  magnesite,  but  carries  a  varying  amount, 
sometimes  as  high  as  40  per  cent  of  intermixed  calcite  and  other 
impurities. 

In  Styria  the  magnesite  lies  among  beds  of  Silurian  age,  consisting 
of  argillaceous  shales,  quartzites,  dolomites,  and  limestones  resting 
upon  gneiss.  The  beds  in  the  Swiss  Tyrol  are  said  to  be  associated 
with  subcarboniferous  limestone.  The  Grecian  deposits  are  on  the 
island  of  Euboea  on  the  eastern  coasts.  According  '.o  a  writer  in 

1  Pacific  Railroad  Reports,  V,  p.  308. 

2  Bulletin  No.  355,  U.  S.  Geological  Survey,  1908. 


156  THE  NON-METALLIC  MINERALS. 

the  Journal  of  the  Society  of  Chemical  Industry  for  May  31,  1909, 
the  principal  deposits  of  Indian  magnesite  lie  in  the  "  Chalk  Hills," 
two  miles  from  the  town  of  Salem  in  the  Madras  Presidency,  where 
they  cover  an  area  of  some  2,000  acres,  occurring  in  abundant 
irregular  veins  of  unknown  depth,  but  having  a  total  aggregate  of 
some  60  feet  in  thickness.  These  veins  are  in  dunite  which  has 
undergone  alteration  into  serpentine  with  the  usual  secondary  magne- 
site, chalcedony,  etc. 

Uses. — In  its  raw  state  magnesite  is  used  as  a  source  of  carbon 
dioxide  the  gas  being  obtained  by  calcining  the  material  in  retorts. 
The  residue  is  so'd  to  makers  of  efractory  bricks,  which  are  used  for 
basic  furnaces  The  calcined  material  is  commercially  classified, 
according  to  the  temperature  which  has  been  employed,  as  (a)  cal- 
cined or  caustic  magnesia  and  (b)  dead  burnt,  sintered,  or  shrunk 
magnesia.  The  caustic  magnesia  is  obtained  by  calcining  at  a 
temperature  of  800°  C.  It  is  used  for  Sorel  or  oxychloride  cements, 
fireproof  partitions,  plaster,  artificial  stone,  steam  packing,  flooring, 
grindstones,  millstones,  emery  wheels,  etc.  Large  quantities  are 
used  in  paper  manufacture.  Sorel  cement  is  formed  by  mixing  the 
caustk  magnesia  with  a  solution  of  magnesian  chloride.  This 
cement  is  very  hard,  white,  and  of  great  durability. 

Th.  Schlossing  has  proposed 1  to  utilize  magnesian  hydrate 
obtained  by  precipitation  from  sea  water  by  lime  for  the  preparation 
of  fire-brick,  the  hydrate  being  first  dehydrated  by  calcination  at  a 
white  heat,  after  which  it  is  made  up  into  brick  form. 

According  to  the  Industrial  World  2  magnesite  as  a  substitute 
for  barite  in  the  manufacture  of  paint  is  likely  to  prove  of  impor 
tance.     The  color,  weight,  and  opacity  of  the  powder  add  to  its 
value  for  this  purpose.     In  Europe  it  is  stated  the  material  is  used 
as  an  adulterant  for  the  cheaper  grades  of  soap. 

Prices. — During  1907  the  material,  96  to  98  per  cent  pure,  was 
quoted  as  worth  $6  to  $8  a  ton  in  New  York  City.  Material 
containing  as  high  as  15  to  30  per  cent  silica  and  8  to  10  per  cent 
of  iron  is  said  to  be  practically  worthless.  Crude  magnesite  is 

1  Comptes  Rendus,  1885,  p.  137. 

2  Industrial  World,  XXXVI,  No.  20,  1891. 


FIG.  i. — Magnesite  Outcrop,  Hixon  Ranch,  Mendocino  County,  California. 
[After  F.  L.  Hess,  Bulletin  No.  355,  U.  S.  Geological  Survey.] 


FIG.  2. — Sonoma  Magnesite  Mine,  near  Cazadero,  California. 
[After  F.  L.  Hess,  Bulletin  No.  355,  U.  S.  Geological  Survey.] 


PLATE  XVI. 


[Facing  page  156. 


CARBONATES.  157 

quoted  as  worth  from  $3  to  $4  a  ton  at  the  mines  in  California. 
The  calcined  material,  the  form  in  which  it  is  sold  to  paper  manu- 
facturers, brings  from  $12  to  $20  a  ton.  It  requires  about  2.4  tons 
of  crude  to  make  one  ton  of  calcined. 


4.    WITHERITE.    . 

This  is  a  carbonate  of  barium  of  the  formula  BaCo3,=  baryta, 
77.7  per  cent,  carbon  dioxide,  22.3  per  cent.  Color,  white  to  yellow 
or  gray,  streak  white;  translucent.  Hardness,  3  to  3.75;  specific 
gravity,  4.29  to  4.35.  When  crystallized,  usually  in  form  of 
hexagonal  prisms,  with  faces  rough  and  longitudinally  striated. 
Common  in  globular  and  botryoidal  forms,  amorphous,  columnar, 
or  granular  in  structure.  The  powdered  mineral  dissolves  readily 
in  hydrochloric  acid,  like  calcite,  but  is  easily  distinguished  from 
this  mineral  by  its  great  weight  and  increased  hardness,  as  well  as  by 
its  vitreous  luster  and  lack  of  rhomboidal  cleavage,  which  is  so 
pronounced  a  feature  in  calcite.  From  barite,  the  sulphate  of  barium, 
with  which  it  might  become  confused  on  account  of  its  high  specific 
gravity,  it  is  readily  distinguished  by  its  solubility  in  acids  as  above 
noted.  From  strontianite  it  can  be  distinguished  by  the  green  color 
it  imparts  to  the  blow-pipe  flame. 

Localities  and  mode  of  occurrence. — The  mineral  occurs  appar- 
ently altogether  as  a  secondary  product  filling  veins  and  clefts  in  older 
rocks  and  often  forming  a  portion  of  the  gangue  material  of  metal- 
liferous deposits.  The  principal  localities  as  given  by  Dana  are 
Alston  Moor,  Cumberland,  where  it  h  associated  with  galena;  in 
large  quantities  at  Fallowfield,  near  Hexam  in  Northumberland;  at 
Anglezarke  in  Lancashire;  at  Arkendale  in  Yorkshire,  and  near 
St.  Asaph  in  Flintshire,  England;  Tarnowitz,  Silesia;  Szlana, 
Hungary ;  Leogang  in  Salzburg ;  the  mine  of  Arqueros  near  Co- 
quimbo,  Chile;  L.  Etang  Island;  near  Lexington,  Kentucky,  and 
in  a  silver-bearing  vein  near  Rabbit  Mountain,  Thunder  Bay,  Lake 
Super'or. 

Uses. — The  mineral  has  been  used  to  but  a  slight  extent  in  the 
arts.  As  a  substitute  for  lime  it  has  met  with  a  limited  application 


15 8  THE  NON-METALLIC  MINERALS. 

:  n  making  plate  glass,  and  is  also  said  to  have  been  used  in  the  manu- 
facture of  beet-sugar,  but  is  now  being  superseded  by  magnesite. 

5.    STRONTIANITE. 

This  is  a  carbonate  of  strontium,  SrCO3,  =  carbon  dioxide,  29.9 
per  cent;  strontia,  70.1  per  cent.  Often  impure  through  the  presence 
of  carbonates  and  sulphates  of  barium  and  calcium.  Colors,  white 
to  gray,  pale  green,  and  yellowish.  Hardness,  3.5  to  4.  Specific 
gravity  3.6  to  3.7.  Transparent  to  translucent.  When  crystallized 
often  in  acute,  spear-shaped  forms.  Also  in  graunlar,  fibrous,  and 
columnar  globular  forms.  Soluble  like  calcite  in  hydrochloric  acid, 
with  effervescence,  but  readily  distinguished  by  its  cleavage  and 
greater  density.  The  powdered  mineral  when  moistened  with  hydro- 
chloric acid  and  held  on  a  platinum  wire  in  the  flame  of  a  lamp 
imparts  to  the  flame  a  very  characteristic  red  color. 

Occurrence. — According  to  Dana  the  mineral  occurs  at  Strontian 
in  Argyllshire,  in  veins  traversing  gneiss,  along  with  galena  and 
barite;  in  Yorkshire,  England;  at  the  Giant's  Causeway,  Ireland; 
Clausthal  in  the  Harz;  Braunsdorf,  Saxony;  Leogang  in  Salzburg; 
near  Brixlegg,  Tyrol;  near  Hamm  and  Minister,  Westphalia.  In 
the  United  States,  at  Schoharie,  New  York,  in  the  form  of  granular 
and  columnar  masses  and  also  in  crystals,  forming  nests  and  geodes 
in  the  hydraulic  limestone;  at  Clinton,  Oneida  County;  Chaumont 
Bay  and  Theresa,  Jefferson  County;  and  Mifflin  County,  Pennsyl- 
vania. 

Uses. — Strontianite,  so  far  as  the  writer  has  information,  has  but 
a  limited  application  in  the  arts.  It  is  stated1  that  "  basic  bricks" 
are  prepared  from  it  by  mixing  the  raw  or  burnt  Strontianite  with 
clay  or  argillaceous  ironstone  in  such  proportions  that  the  brick 
shall  contain  about  10  per  cent  of  silica,  and  then  working  it  into  a 
plastic  mass  with  tar  or  some  heavy  hydrocarbon.  After  molding, 
the  bricks  are  dusted  with  fine  clay  or  ironstone,  dried,  and  burned. 
The  effect  of  the  dusting  is  to  form  a  glaze  on  the  surface,  which 
protects  the  brick  from  the  moisture  of  the  air.  Like  celestite,  it 

1  Journal  of  the  Society  of  Chemical  Industry,  III,  1884,  p.  33. 


CARBONATES.  159 

is  also  used  in  the  production  of  the  red  fire  of  fireworks.  The 
demand  for  the  material  is  small,  and  the  price  but  from  $2.50  to 
$4  a  ton. 

6.    RHODOCHROSITE ;   DIALOGITE. 

This  is  a  pure  manganese  carbonate  of  the  formula  MnCO3,  = 
carbon  dioxide,  38.3  per  cent;  manganese  protoxide,  61.7  per  cent. 
The  color  is  much  like  that  of  rhodonite  (see  p.  204),  from  which, 
however,  it  is  readily  distinguishable  by  its  rhombohedral  form, 
inferior  hardness  (3.5  to  4.5),  and  property  of  dissolving  with  effer- 
vescence in  hot  hydrochloric  acid,  while  rhodonite  is  scarcely  at 
all  attacked.  The  mineral  is  a  common  constituent  of  the  gangue 
of  gold  and  silver  ores,  as  at  Butte,  Montana;  Austin,  Nevada,  etc. 
So  far  as  known  the  mineral  has  as  yet  no  commercial  value. 

7.    NATRON,    THE   NITRUM   OF   THE   ANCIENTS. 

This  is  a  hydrous  sodium  carbonate,  Na2CO3  +  ioH2O,  =  carbon 
dioxide,  15.4  per  cent;  soda,  21.7  per  cent;  water,  62.9  per  cent. 
Occurs  in  nature,  according  to  Dana,  only  in  solution,  as  in  the 
soda  lakes  of  Egypt  and  elsewhere,  or  mixed  with  other  sodium  car- 
bonates. The  artificially  crystallized  material  is  of  white  color 
when  pure,  soft,  and  brittle,  and  with  an  alkaline  taste.  Crystals, 
thin,  tabular,  monoclinic.  Thermonatrite,  also  a  hydrous  sodium 
carbonate  of  the  formula  Na2CO3  +  H2O,  =  carbon  dioxide,  35.5 
per  cent;  soda,  50  per  cent,  and  water  14.5  per  cent,  occurs  under 
similar  conditions,  and  is  considered  as  derived  from  natron  as  a 
product  of  efflorescence.  (See  further  under  Sodium  sulphates, 

P-  333-) 

8.  TRONA;  URAO. 

This  is  a  hydrous  sodium  carbonate,  corresponding  to  the  for- 
mula Na2CO3.HNaCO3  +  2H2O,  =  carbon  dioxide,  38.9  per  cent; 
soda,  41.2  per  cent;  water,  19.9  per  cent. 

Found  in  nature  as  an  efflorescence  or  incrustation  from  the 
evaporation  of  lakes,  particularly  those  of  arid  regions.  W.  P. 
Blake  has  recently  described1  crude  carbonate  of  soda  (Trona) 

1  Engineering  and  Mining  Journal,  LXV,  1898,  p.  188. 


i6o 


THE  NON-METALLIC  MINERALS. 


occurring  in  the  central  portion  of  a  basin-shaped  depression  or 
dry  lake  in  southern  Arizona,  near  the  head  of  the  Gulf  of  California. 
The  deposit  covers  an  area  of  some  60  acres  to  a  depth  of  from  i  to 
3  feet,  the  lower  portion  being  saturated  with  water  from  a  solution 
so  strong  that  when  exposed  to  the  air  soda  is  deposited  at  the  rate 
of  an  inch  in  thickness  for  every  ten  days.  In  its  native  condition 
the  soda  is  naturally  somewhat  impure,  from  silt  blown  in  from 
the  surrounding  land.  The  analysis  given  below  shows  the  general 
average: 


Constituents. 

Per  Cent. 

Sand  silt  etc              

13  .00 

Iron  oxides  and  alumina  

2.80 

1  .14 

Salt  (NaCl  ) 

47O 

Sulphate  of  soda 

47O 

Carbonate  of  soda 

71  66 

100.00 

See  further  under  Thernardite,  p. . 

BIBLIOGRAPHY    OF   LIMES   AND   CEMENTS. 

Out  of  the  many  hundreds  of  titles  that  might  be  given,  a  few  only  are  selected. 
Those  desiring  may  find  a  very  full  bibliography  in  a  series  of  papers  on  The  Chemi- 
cal and  Physical  Examinations  of  Portland  Cement.     Journal  of  the  American  Chemi- 
cal Society,  XV  and  XVI.     1893-1894. 
Q.  A.  GILLMORE.    Practical  treatise  on  Limestones,  Hydraulic  Cements,  and  Mortars. 

New  York,  1863,  333  pp. 
The  Cement  Works  on  the  Lehigh. 

Second  Pennsylvania  Geological  Survey,  Lehigh  District,  D.  D.  1875-76,  p.  59. 
HENRY  C.  E.  REID.     The  Science  and  Art  of  the  Manufacture  of  Portland  Cement 
with  Observations  on  some  of  its  Constructive  Applications. 

London,  1877. 

JOHANN  BIELENBERG.  Method  for  Utilizing  Siliceous  Earths  and  Rocks  in  the 
Manufacture  of  Cements,  for  the  purpose  of  imparting  to  them  Hydraulic  Proper, 
ties.  (German  Patent  No.  24038,  November  28,  1882.) 

Journal  of  the  Society  of  Chemical  Industry,  III,  1884,  p.  no. 
U.  CUMMINGS.     Hydraulic  Cements,  Natural  and  Artificial,  their  Comparative  Values. 

Massachusetts  Institute  of  Technology,  November,  1887. 

M.  H.  LE  CHATELIER.  Recherches  Experimentales  sur  la  Constitution  des  Mortiers. 
Hydrauliques. 

Chas.  Dunod,  Paris,  1887. 


SILICATES.  161 

M.  A.  PROST.     Note  sur  la  Fabrication  et  les  Proprietes  des  Ciments  de  Laitier 

Annales  des  Mines,  XVI,  1889,  p.  158. 
H.  PEARETH  BRUMELL.     Natural  and  Artificial  Cements  in  Canada. 

Science,  XXI,  1893,  p.  177. 
M.  H.  LE  CH ATELIER.     Precedes  d'Essai  des  Materiaux  Hydrauliques. 

Annales  des  Mines,  IV,  1893,  p.  367. 
A.  H.  HEATH.     A  Manual  of  Lime  and  Cement. 

London,   1893,   215  pp. 
G.  R.  REDGRAVE.     Calcareous  Cements:  Their  Nature  and  Uses. 

London,    1895,   222  pp. 
URIAH  CUMMINGS.     American  Cements. 

Boston,  1898,  299  pp. 
CHARLES  D.  JAMESON.     Portland  Cement,  its  Manufacture  and  Use. 

New  York,  1898,  192  pp. 
BERNARD  L.  GREEN.     The  Portland  Cement  Industry  of  the  World. 

(Reprinted  from  Journal  of  the  Association  of  Engineering  Societies.     XX, 
June,   1898.) 
E.  C.  ECKEL.     Cements,  Limes  and  Plasters.     Wiley  &  Sons,  New  York,  1905. 


VI.  SILICATES. 

I.    FELDSPARS. 

The  name  feldspar  is  given  to  a  group  of  minerals  resembling 
each  other  in  being,  chemically,  silicates  of  aluminum  with  varying 
amounts  of  lime  and  the  alkalies  potash  and  soda.  All  members 
of  the  group  have  in  common  two  easy  cleavages  whereby  they 
split  with  even,  smooth,  and  shining  surfaces  along  planes  inclined 
to  one  another  at  angles  of  nearly  if  not  quite  90°.  They  vary 
from  transparent  through  translucent  to  opaque,  the  opaque  form 
being  the  more  frequent.  In  colors  they  range  from  clear  and 
colorless  through  white  and  all  shades  of  gray  to  yellowish,  pink,  and 
red,  more  rarely  greenish. 

On  prolonged  exposures  to  the  weather  they  become  whitish 
and  opaque,  gradually  decomposing  into  soluble  carbonates  of 
lime  and  the  alkalies,  and  soluble  silica,  any  one  of  which  may  be 
wholly  or  in  part  removed  by  percolating  waters,  leaving  behind  a 
residual  product,  consisting  essentially  of  hydrous  silicates  of  alu- 
mina, to  which  the  names  kaolin  and  clay  are  given  (see  p.  217). 
The  hardness  of  the  feldspars  varies  from  5  to  7  of  Dana's  scale; 


162 


THE  NON-METALLIC  MINERALS. 


specific  gravity  2.5  to  2.8  They  are  fusible  only  with  difficulty,  and 
with  the  exception  of  the  mineral  quartz  are  the  hardest  of  the 
common  light-colored  minerals.  From  quartz  they  are  readily 
distinguished  by  their  cleavage  characteristics  noted  above.  Geolog- 
ically the  feldspars  belong  to  the  gneisses  and  eruptive  rocks  of 
all  ages,  certain  varieties  being  characteristic  of  certain  rocks  and 
furnishing  important  data  for  schemes  of  rock  classification.  Nine 
principal  varieties  are  recognized  which  on  crystallographic  grounds 
are  divided  into  two  groups.  The  first,  crystallizing  in  the  mono- 
clinic  system,  including  only  the  varieties  orthoclase  and  hyalophane ; 
the  second,  crystallizing  in  the  triclinic  system,  including  micro- 
clinic,  anorthoclase,  and  the  albite-anorthite  series,  albite,  oligo- 
clase,  andesine,  labradorite,  and  anorthite.  The  above-mentioned 
properties  are  set  forth  in  the  accompanying  table. 


Constituents. 

Ortho- 
clase. 

Hyalo- 
phane. 

Micro- 
cline. 

Anor- 
thociase 

Albite. 

Oligo- 
clase. 

Ande- 
sine. 

Labra- 
dorite. 

Anor- 
thite. 

Silica,  SiO2  
Alumina.  A]2O3 
Potash,  K2O  .  . 
Soda,  Na2O.  .  .  . 
Barium,  BaO.  . 
Lime,  CaO.  .  .  . 
Specific  grav.  .  . 
Hardness  

Crystalline  sys- 
tem   

64.7 
18.4 
16.9 

5i.6 

21  .Q 
10.  I 

64.7 
18.4 
16.9 

66.0 

20.0 

S-o 
8.0 

68.0 

20  .  o 

62.0 
24.0 

60  .  o 
26.0 

53-0 
30.0 

43-o 
37-0 

I  2  .  O 

9.0 

8.0 

4.0 

l6.4 

5-0 
2.56-2.7 
6  .  0—7  .  o 

7.0 

2  .6-2.  7 

5  .  o—  6  .  o 

13-0 
2.6-2.7 
6.0 

20.0 

2.6-2.8 
6.0-7  -o 

2.4-2.6 
6.0-6.5 

2.8 
6.0-6.5 

2  .  4-2  .  6 
6  .  0-6  .  5 

2  .  0-5  .  8 

2.5-2.6 

6.0-7  -o 

Monoclinic.                                                   Triclinic. 
i 

Of  the  above  those  which  most  concern  us  here  are  the  potash 
feldspars  orthoclase  and  microcline,  two  varieties  which  for  our  pur- 
poses are  essentially  identical  both  as  regards  composition  ancf  gen- 
eral physical  properties  as  well  as  mode  of  occurrence.  Indeed, 
although  crystallizing  in  different  systems  they  are  as  a  rule  indis- 
tinguishable but  by  microscopic  means  or  by  careful  crystallographic 
measurements. 

Occurrence. — The  potash  feldspars  are  common  and  abundant 
constitutents  of  the  acid  rocks — such  as  the  granites,  gneisses,  syen- 
ites—the orthoclase  and  quartzose  porphyries,  and  the  Tertiary -and 
modern  lavas — such  as  trachyte,  phonolite,  and  the  liparites. 

Among  the  older  rocks  they  frequently  occur  in  large  dikes 
or  vein-like  masses  of  coarse  pegmatitic  crystallization,  the  indi- 
vidual crystals  being  in  some  cases  a  foot  or  more  in  diameter.  The 


FIG.  i. — Feldspar  Quarry,  Topsham,  Maine. 
[From  photograph  by  E.  S.  Bastin,  U.  S.  Geological  Survey. 


FIG.  2. — Feldspar  Quarry,  South  Glastonbury,  Connecticut. 
[From  photograph  by  E.  S.  Bastin,  U.  S.  Geological  Survey. 

PLATE  XVII. 

[Facing  page  162.] 


SILICATES.  163 

associated  minerals  are  quartz  and  white  mica,  with  beryl,  tour- 
maline, garnet,  and  a  great  variety  of  rarer  minerals.  The  ordinary 
white  mica  of  commerce  comes  from  deposits  of  this  nature  and 
often  the  two  minerals  are  mined  contemporaneously.  Such  of 
our  feldspars  as  have  yet  been  worked  for  ecomomic  purposes  occur 
associated  only  with  the  older  rocks — the  granites  and  gneisses 
of  the  Archean  and  Lower  Paleozoic  formations. 

Near  Topsham,  Maine,  is  one  of  these  pegmatitic  intrusions, 
running  parallel  with  the  strike  of  gneissoid  schists  in  which  it  lies,  i.e., 
northeast  and  southwest.  The  quarry  is  in  the  form  of  an  open  cut 
in  the  hillside,  some  300  feet  long  by  100  feet  wide,  and  of  very 
irregular  contours.  The  present  floor  and  the  sides  of  the  cut  are 
of  feldspar,  containing  irregular  bodies  of  quartz  and  mica,  the 
first  named  occurring  in  large  masses  entirely  free  from  other  min- 
erals, though  a  second  grade  is  taken  out  which  is  in  reality  an  in- 
timate mixture  of  quartz  and  feldspar. 

The  quartz  occurs,  besides  as  mentioned  above,  in  the  form  of 
irregular  bodies,  sometimes  6  or  8  feet  across  and  15  feet  or  more 
long.  It  also  occurs  in  cavities,  or  geodes,  in  the  form  of  flattened 
crystals.  The  mica  is  here  of  little  economic  importance,  being 
embedded  in  the  feldspar  and  occurring  along  the  seams  in  the  form 
of  narrow,  lanceolate  masses,  often  arranged  in  small  radiating  con- 
ical forms  with  their  apexes  outward. 

It  should  be  noted  that  the  rock  pegmatite,  a  coarse  aggregate 
of  quartz  and  feldspar,  is  often  mined  and  utilized  for  the  same 
purpose,  as  is  the  pure  feldspar  itself.  Albite,  when  occurring  with 
the  othoclase,  is  also  mined  and  utilized  in  the  same  manner. 

The  principal  feldspar  quarries  thus  far  worked  are  in  the  eastern 
United  States,  from  Maine  to  New  Jersey.  The  material  is  mined 
from  open  cuts,  being  blasted  out  with  powder  and  separated  from 
adhering  quartz,  mica,  and  other  minerals  by  hand,  after  which  it 
is  shipped  in  the  rough  to  the  potteries,  or  in  some  cases  ground  and 
bolted  in  the  near  vicinity.  In  times  past  the  material  has  been 
ground  under  huge  granite  disks  mounted  like  the  wheels  of  a  cart 
on  an  axle  through  the  center  of  which  extended  a  vertical  shaft. 
By  the  slow  revolution  of  this  shaft  the  wheels  traveled  around  in 
a  limited  circle  over  a  large  horizontal  granite  slab.  The  pieces  of 


1 64  THE  NON-METALLIC  MINERALS. 

spar  being  placed  upon  the  horizontal  slab  were  thus  slowly  ground 
to  powder.  A  more  modern  method  is  by  means  of  the  so-called 
Cyclone  crusher.  The  value  of  the  uncrushed  material  delivered 
at  the  potteries  is  but  a  few  dollars  a  ton.  Hence,  while  there  are 
unlimited  quantities  of  the  material  in  different  parts  of  the  Appa- 
lachian region,  but  few  are  so  situated  as  to  profitably  worked. 

Uses. — The  feldspars  are  used  mainly  for  pottery,  being  mixed 
in  a  finely  pulverized  condition  with  the  kaolin  or  clay.  When 
subjected  to  a  high  temperature  the  feldspar  fuses,  forming  a  glaze 
and  at  the  same  time  a  cementing  constituent.  There  are  other 
substances  more  readily  fusible  which  are  utilized  for  this  purpose 
in  the  cheaper  kinds  of  ware,  but  it  is  stated  that  in  the  highest 
grades  of  porcelain,  as  those  of  Sevres,  feldspar  is  the  material  used. 
The  proportions  used  vary  with  different  manufacturers,  each  having 
adopted  a  formula  best  adapted  for  his  own  workings. 

For  more  than  fifty  years  experiments  have  from  time  to  time 
been  made  with  a  view  of  extracting  the  potash  from  feldspars  on 
a  commercial  scale  and  also  of  using  the  ground  feldspar  in  its  crude 
or  raw  state  as  a  fertilizer.  The  cheapness  of  the  Stassfurth  potash 
salts  has  thus  far  militated  against  the  development  of  the  first-named 
industry,  and  while  experiment  has  shown  that  plants  will  assimilate 
a  certain  amount  of  potash  from  the  raw,  finely  ground  feldspar, 
the  effect  of  such  application  has  not  proven  sufficient  to  warrant  its 
general  adoption. 

In  the  same  way  attempts  have  been  made  to  utilize  the  potash 
of  the  nepheline  in  phonolites,  but  the  results  have  been  unsuccessful, 
owing  to  the  insoluble  character  of  the  silicate.1 

The  labrador  feldspar  occurring  as  the  chief  constituent  of  a 
gabbro  near  Duluth,  Minnesota,  is  crushed  and  made  into  sandpaper 
for  use  in  woodworking. 

2.  MICAS. 

Under  this  head  are  comprised  a  number  of  distinct  mineral 
species,  alike  in  crystallizing  in  the  monoclinic  system  and  having  a 
highly  perfect  basal  cleavage,  whereby  they  split  readily  into  thin, 
translucent  to  transparent,  more  or  less  elastic  sheets.  Chemically 

1  Deut.  Landes.  Presse,  XXXVI,  1909. 


SILICATES. 


165 


they  are  in  most  cases  orthosilicates  of  aluminum  with  potassium 
and  hydrogen,  and  in  some  varieties  magnesium,  ferrous  and  ferric 
iron,  sodium,  lithium,  and  more  rarely  barium,  manganese,  titanium, 
and  chromium.  Seven  species  of  mica  are  commonly  recognized, 
of  which  but  three  have  any  commercial  value,  though  a  fourth 
form,  lepidolite,  may  perhaps  be  utilized  as  a  source  of  lithia  salts, 
and  a  fifth,  roscoelite,as  a  source  of  salts  of  vanadium.  Of  these  three 
forms  the  white  mica,  muscovite,  and  the  pearl-gray  phlogopite  are 
of  greatest  importance,  the  black  variety,  biotite,  being  but  little 
used.  Muscovite,  or  potassium  mica,  is  essentially  a  silicate  of  alu- 
minum and  potassium,  with  small  amounts  of  iron,  soda,  magnesia, 
and  water.  Its  color  is  white  to  colorless,  often  tinted  with  brown, 
green,  and  voilet  shades.  When  crystallized  it  takes  on  hexagonal 
or  diamond-shaped  forms,  as  do  also  phlogopite  and  biotite.  Its 
industrial  value  lies  in  its  great  power  of  resistance  to  heat  and  acids, 
its  transparency,  and  its  wonderful  fissile  property,  in  virtue  of  which 
it  may  be  split  into  extremely  thin,  flexible  sheets.  Phlogopite, 
or  magnesian  mica,  differs  from  muscovite  in  being  of  a  darker,  deep 
pearl-gray,  sometimes  smoky,  often  yellowish,  brownish  red,  or 
greenish  color  and  lacking  in  transparency.  Biotite,  or  magnesia 
iron  mica,  differs  in  being  often  deep,  almost  coal  black  and  opaque 
in  thick  masses,  though  translucent  and  of  a  dark-brown,  yellow, 
green,  or  red  color  in  thin  folia.  It  further  differs  from  the  preceding 
in  that  its  folia  are  less  elastic,  and  the  sheets  of  smaller  size.  Lep- 
idolite, a  lithia  mica,  is  much  more  rare  than  either  of  the  above,  is 
of  a  pale  rose  or  pink  color,  the  folia  usually  of  small  size,  commonly 
occurring  in  scaly  granular  forms  without  crystal  outlines.  The 
following  table  will  serve  to  show  the  varying  composition  of  the 
four  varieties  mentioned : 


Variety. 

SiO2. 

A1203. 

Fe203. 

FeO. 

MgO. 

CaO. 

K20. 

Na20. 

F. 

H20. 

Muscovite  
Phlogopite  

45-71 
44  •  4^ 
45-40 
39-66 
43-00 
40  .  64 

36.57 
35-70 
33-66 
17  .00 
13-27 
14.11 

1.19 
i  .09 
2.36 
0.27 
1.71 
2.28 

i  .07 
1.07 

o  .  20 
o  .  69 

0.71 
Trace. 
1.86 
26.49 
27  .70 
27  .  97 

0.46 
o  .  10 

9.22 
9-77 

8.33 
9-97 
10.32 
8.16 

0-79 
2.41 
1.41 
0.60 
0.30 
1.16 

0.12 
0.72 
0.69 
2.24 
5-67 
0.82 

4-83 
5-50 
5-46 
2-99 

0.78 

3-21 

Biotite  

31  .  69 

4-75 

3  •  9° 

.... 

8.00 

o  .  59 

o  .  93 

3.85 

Lepidolite  

34-67 
39-3° 
40  .  1  6 
50.39 
49.62 

30.09 
16.95 
15-79 
28.  19 

27.30 

2.42 
0.48 
2-53 

0.31 

16.99 
8.45 
4.12 

0.07 

1.98 

2  I.  .89 
26.15 

5-08 

4-34 

'.'.'.'.'. 

'0.82 

Li2O  ' 
Li20 

7-55 
7-79 
7.64 
12.34 
11.19 

1-57 
0.49 
0.37 

2.17 

0.28 
0.89 

5-15 
5-45 

4.64 

4.02 

3.58 

2.36 
1.52 

1 66  THE  NON-METALLIC  MINERALS. 

Although  the  basal  cleavage  which  permits  of  the  ready  splitting 
of  the  mica  into  thin  sheets  is  the  only  one  sufficiently  developed 
to  be  of  economic  importance,  the  mica  as  found  is  often  traversed 
by  sharp  lines  of  separation,  called  gliding  planes,  which  may,  by 
their  abundance,  be  disastrous  to  the  interests  of  the  miner.  Such 
partings,  or  gliding  planes,  supposed  to  be  induced  by  pressure, 
are  developed  at  angles  of  about  66J°  with  the  cleavage,  and  may 
cut  entirely  through  a  block  or  extend  inward  from  the  margin  only 
a  short  distance  and  come  to  an  abrupt  stop.  In  many  cases  these 
planes  divide  the  mica  into  long  narrow  strips,  from  the  breadth  of  a 
line  to  several  inches  in  thickness,  with  sides  parallel,  and  as  sharply 
cut  as  though  done  with  shears. 

The  imperfections  in  mica  are  due  to  inclosures  of  foreign  min- 
erals, as  flattened  garnets,  to  the  presence  of  free  iron  oxides,  often 
with  a  most  beautiful  dendritic  structure,  to  the  partings  or  gliding 
planes  noted  above,  and  to  crumplings  and  V-like  striations  which 
destroy  its  homogeneity. 

Occurrence. — Mica  in  quantity  and  sizes  to  be  of  economic 
importance  is  found  only  among  the  older  rocks  of  the  earth's  crust, 
particularly  those  of  the  granite  and  gneissoid  groups.  Musco- 
vite and  biotite  are  among  the  commonest  constituents  of  siliceous 
rocks  of  all  kinds  and  ages,  while  phlogopite  is  more  characteristic 
of  calcareous  rocks.  It  is,  however,  only  when  developed  in  crystals 
of  considerable  size  in  pegmatitic  and  coarsely  feldspathic  veins, 
or,  in  the  case  of  phlogopite,  in  gneissic  and  calcareous  rocks  asso- 
ciated with  eruptive  pyroxenites,  that  it  becomes  available  for  eco- 
nomic purposes.  The  associated  minerals  are  almost  too  numerous 
to  mention.  The  more  common  for  muscovite  are  quartz  and 
potash  feldspar,  which  form  the  chief  gangue  materials  in  crystals 
and  crystalline  masses,  sometimes  a  foot  or  more  in  diameter.  With 
these  are  almost  invariably  associated  garnets,  beryls,  and  tour- 
malines, with  more  rarely  cassiterite,  columbite,  apatite,  fluorite, 
topaz,  spodumene,  uraninite,  etc.  Indeed,  so  abundant  are,  at  times, 
the  accessory  minerals  in  the  granitic  veins,  and  so  perfect  their 
crystalline  development,  that  they  furnish  by  far  the  richest  collecting 
grounds  for  the  mineralogists.  Of  these  minerals  the  quartz  and 


SILICATES.  167 

feldspars  are  not  infrequently  mined  contemporaneously  with  the 
mica  and  utilized  in  the  manufacture  of  pottery  and  abrasives. 

Origin. — It  is  now  commonly  assumed  that  these  pegmatitic 
" veins"  are  undoubted  intrusives,  though  to  some  authorities  it 
seems  scarcely  possible  that  the  extremely  coarse  aggregates  of  quartz, 
feldspar,  and  mica,  with  large  garnets,  beryls,  and  tourmalines,  can 
be  a  direct  result  of  cooling  from  an  igneous  magma.  To  such  it 
appears  more  probable  that  they  are  portions  of  an  original  rock 
mass  altered  by  exhalations  of  fluorhydric  acids,  like  the  Saxon 
"greisen."  Others  regard  them  as  resulting  from  the  very  slow 
cooling  of  granitic  material  injected  in  a  pasty  condition,  brought 
about  by  aqueo-igneous  agencies,  into  rifts  of  the  pre-existing  rocks. 
It  must  be  remembered  that  the  high  degree  of  dynamic  metamorph- 
ism  which  these  older  rocks  have  undergone  renders  the  problems 
relating  to  their  origin  extremely  difficult.  As  to  the  origin  of  the 
Canadian  phlogopite  there  seems  no  reason  for  not  adopting  the 
conclusion  of  Cirkel,  who  regards  it  as  a  product  of  crystallization 
from  an  aqueo-igneous  solution,  which  permeated  upward  along 
lines  of  fracture  either  in  pyroxenic  rocks  or  along  the  line  of  contact 
between  these  rocks  and  the  prevailing  gneisses  and  limestones. 

The  common  association  of  apatite  with  the  phlogopite  indicates 
a  common  and  practically  contemporaneous  origin  for  both. 

Localities. — From  what  has  been  said  regarding  occurrences,  it 
is  evident  that  mica  deposits  are  to  be  found  mainly  in  regions 
occupied  by  the  older  crystalline  rocks.  In  the  United  States, 
therefore,  one  need  look  for  them  only  in  the  States  bordering  im- 
mediately along  the  Appalachian  range  and  in  the  granitic  areas 
west  of  the  front  range  of  the  Rocky  Mountains.1  In  the  Appa- 
lachian region  south  of  Canada  mica  mines,  worked  either  for  mica 
alone  or  for  quartz  and  feldspar  in  addition,  have  from  time  to 
time  been  opened  in  various  parts  of  Maine,  New  Hampshire, 
Connecticut,  Maryland,  Virginia,  North  Carolina,  and  perhaps 
other  States,  but  in  none  of  them,  with  the  exception  of  New  Hamp- 
shire and  North  Carolina,  has  the  business  proven  sufficiently 
lucrative  to  warrant  continuous  and  systematic  working.  Indeed, 

1  The  region  of  the  Black  Hills  of  South  Dakota  is  an  important  exception. 


i68  THE  NON-METALLIC  MINERALS. 

were  it  not  for  the  increased  demand  lately  arising  for  the  use  of 
mica  in  electrical  machines  it  is  doubtful  if  any  but  the  most  favorably 
situated  mines  would  remain  longer  in  operation  in  the  United 
States.  This  for  the  reason  not  so  much  that  foreign  mica  is  better 
as  that  it  is  cheaper. 

Muscovite. — In  Maine  muscovite  has  been  mined  in  an  inter- 
mittent manner  along  with  quartz  and  feldspar  at  the  well-known 
mineral  localities  at  Paris  Hill  and  Rumford,  Oxford  County;  Au- 
burn, Androscoggin  County;  Topsham,  Sagadahoc  County;  Edge- 
comb,  Lincoln  County,  and  other  counties  in  the  southeastern  part 
of  the  State.  In  New  Hampshire  the  industry  has  assumed  greater 
importance.  The  mica-bearing  belt  is  described  by  Professor  C.  H. 
Hitchcock  as  usually  about  2  miles  in  width,  and  extending  from 
Easton,  in  Graf  ton  County,  to  Surry,  in  Cheshire  County;  being  best 
developed  about  the  towns  of  Rumney  and  Hebron.  The  mica 
occurs  in  immense  coarse  granite  veins  in  a  fibrolitic  mica  schist, 
and  is  found  in  sheets  sometimes  a  yard  in  length,  but  the  more 
common  sizes  are  but  10  or  12  inches  in  length.  Immense  beryls, 
sometimes  a  yard  in  diameter,  and  beautiful  large  tourmalines  occur 
among  the  accessory  minerals.  Mines  for  mica  were  opened  at 
Graf  ton  as  early  as  1840,  and  as  many  as  six  or  eight  mines  have 
been  worked  at  one  time,  though  by  no  means  continually.  Other 
mines  have  been  worked  in  Groton,  Alexandria,  Grafton,  and 
Alstead,  in  Grafton  County;  Acworth  and  Springfield,  Sullivan 
County;  Marlboro,  Cheshire  County;  New  Hampton,  Belknap 
County,  and  Wilmot,  Merrimack  County. 

As  seen  by  the  present  writer,  in  1894  the  veins  in  Grafton  County 
cut  sharply  across  the  fibrolitic  schist,  and  though  the  vein  materials 
adhere  closely  to  the  wall  rock  on  either  side,  without  either  selvage 
or  slickensides,  still  the  line  of  demarcation  is  perfectly  sharp. 
There  seems  no  room  for  doubt  but  that  the  vein  material  was 
derived  by  injection  from  below,  though  from  their  extremely  irreg- 
ular and  universally  coarsely  crystalline  condition  we  must  infer 
that  the  condition  of  the  injected  magma  was  more  in  the  nature 
of  solution  than  fusion,  as  the  word  is  ordinarily  used,  and  also 
that  the  rate  of  cooling  and  consequent  crystallization  was  very 
slow.  The  feldspars  frequently  occur  in  huge  crystalline  masses 


SILICATES.  169 

several  feet  in  diameter,  though  sometimes  more  finely  intercrystal- 
lized  with  quartz  in  the  form  known  as  pegmatite.  The  mica  is 
by  no  means  disseminated  uniformly  throughout  the  vein,  but  on 
the  contrary  is  very  sporadic,  and  the  process  of  mining  consists 
merely  in  following  up  the  mineral  wherever  indications  as  shown 
in  the  face  of  the  quarry  are  sufficiently  promising.  Most  of  the 
mines  are  in  the  form  of  open  cuts  and  trenches,  though  in  a  few 
instances  underground  cuts  have  been  made  for  a  distance  of  a 
hundred  feet  or  more.  The  mica  blocks  as  removed  are  of  a  beautiful 
smoky-brown  color,  and  often  show  a  distinct  zonal  structure,  in- 
dicating several  periods  of  growth.  The  associated  feldspar  is 
not  in  all  cases  orthoclase,  but,  as  at  the  Alexandria  mines,  some- 
times a  faint  greenish  triclinic  variety. 

In  Connecticut  some  mica  (muscovite)  has  been  obtained  in 
connection  with  the  work  of  mining  feldspar  and  quartz  in  and 
about  the  towns  of  Haddam,  Glastonbury,  and  Middletown,  but  the 
business  has  never  assumed  any  importance. 

South  of  the  glacial  limit  mica  mining  has  proven  more  successful 
from  the  reason  that  the  gangue  minerals  (feldspar  and  quartz)  are 
in  a  state  of  less  compact  aggregation,  due  to  weathering,  the  feldspar 
being  often  reduced  to  the  state  of  kaolin,  and  hence  readily  removed 
by  pick  and  shovel. 

North  Carolina. — It  is  for  the  above  reason,  in  part,  that  the 
mica  industry  has  prospered  in  North  Carolina  more  than  elsewhere 
in  the  eastern  United  States.  The  deposits  here  were  first  described 
in  a  systematic  manner  by  W.  C.  Kerr  1  in  1880,  and  have  since  been 
the  subject  of  numerous  investigations  on  the  part  of  the  State  and 
United  States  Geological  Surveys.2  As  in  New  Hampshire  and  else- 
where the  mica  occurs  in  intrusive  masses  of  pegmatite  which  have 
most  frequently  followed  the  lines  of  least  resistance  in  the  inclosing 
Archaean  gneisses  and  schists,  forming  thus  what  Kerr  described 
as  bedded  veins,  although  he  recognized  their  intrusive  character. 

The  area  of  the  mica-bearing  pegmatites  extends  entirely  across 
the  western  part  of  the  State  in  a  northeasterly  and  southwesterly 
direction,  from  Virginia  to  Georgia,  but  the  chief  centers  of  produc- 

1  Transactions  of  the  American  Institute  of  Mining  Engineers,  VIII,  p.  457. 

2  See  D.  B.  Sterrett,  Bulletin  No.  315,  U.  S.  Geological  Survey,  p.  400. 


1 70  THE  NON-METALLIC  MINERALS. 

tion  have  been  in  Mitchell,  Yancey,  Macon,  Jackson,  Haywood, 
Ashe  and  Cleveland  counties.  (See  map,  Fig.  27.)  Sterrett  recog- 
nizes three  zones,  or  belts,  (i)  the  Cowee-Black  mountain,  (2)  the 
Blue  Ridge  and  (3)  the  Piedmont.  The  first  runs  nearly  through 
the  State  parallel  with  its  western  border;  the  second  follows  the 
Blue  Ridge  and  extends  several  miles  to  the  southeast  along  the 
foothills.  It  is  the  least  important  of  the  three.  The  Piedmont  belt 


so  100  iso 200  miles 


Chiefly  clear,  rum-  Principal  areas  Chiefly  dark-colored 

colored  mica.  of  production.  or  speckled  mica. 

FIG.  27. — Map  showing  mica-producing  areas  of  North  Carolina. 
[After  Douglas  Sterrett,  Bulletin  No.  315,  U.  S.  Geological  Survey,  1907. 

lies  southeast  of  the  ridge,  mainly  in  Cleveland,  Lincoln,  Burke  and 
Stokes  counties. 

The  pegmatites  form,  for  the  most  part,  lens-shaped  masses 
conformable  with  the  schistosity  of  the  country  rock  in  one  or  several 
parallel  planes.  In  cross-section  some  are  short  and  bulky,  with  a 
length  but  two  or  three  times  their  thickness,  while  others  are  long 
and  tapering,  often  much  branched,  and  follow  the  windings  and  con- 
tortions of  the  inclosing  rock.  (See  Fig.  .  8.) 

The  size  of  the  dikes  is  variable,  but  as  a  rule  none  are  worked 
of  a  thickness  less  than  one  of  two  feet  and  then  only  when  excep- 


SILICATES. 


171 


•IS 

3     n> 

*I 


S§ 


*f 

Cl     "' 

=  §• 


8  f 


S§ 


O         l-f 

c:    o 

5       H 


£  y  o 

o    o    S 


re    o* 


w  F 

P     3 


g'    « 

o   S1 


172  THE  NON-METALLIC  MINERALS. 

tionally  rich.  As  elsewhere,  the  mica  is  rarely  uniformly  dissemi- 
nated throughout  the  rock,  nor  does  it  keep  the  same  relative  position 
in  any  one  dike  for  long  distances.  In  some  of  the  larger  dikes  the 
rock  is  so  coarsely  crystalline  as  to  yield  cleavage  masses  of  feldspar 
several  tons  in  weight,  and  mention  is  made  of  a  feldspar  crystal 
weighing  nearly  a  thousand  pounds,  and  of  sheets  of  mica  three  and 
four  feet  in  diameter. 

In  Alabama,  along  a  line  stretching  from  Chilton  County,  north- 
east, through  Coosa,  Clay,  and  Cleburne  counties,  there  are  numer- 
ous evidences  of  prehistoric  mica  mining.  Many  pits  are  met  with 
around  which  pieces  of  mica  are  still  to  be  seen.  In  some  places, 
as  in  Mitchell  County,  North  Carolina,  large  pine  trees  have  grown 
up  on  the  de*bris,  so  that  a  considerable  time  must  have  elapsed 
since  the  mines  were  worked. 

In  Colorado  mica  has  long  been  known  to  be  widely  disseminated 
and  to  occur  in  many  places  in  bodies  of  workable  size.  Many 
mines  have  been  located,  but  the  product  has  always  proved  worthless, 
until  in  the  summer  of  1884  the  Denver  Mica  Company  opened  a 
mine  near  Turkey  Creek,  about  35  miles  from  Denver.  This  mica 
is  of  fair  quality,  and  quite  a  considerable  quantity  of  it  has  been 
mined.  It  is  slightly  brown,  and  the  largest  plates  which  have  yet 
been  cut  are  not  more  than  2f  by  6  inches  in  size.  Only  an  extremely 
•  small  percentage  of  the  gross  weight  is  available  for  cutting  into  sheets. 
Mica  of  good  quality  and  large  plates  has  also  been  recently  reported 
from  the  neighborhood  of  Fort  Collins. 

In  Wyoming  mica  has  been  found  in  workable  quantities  near 
Diamond  Park  and  in  the  Wind  River  country,  as  well  as  at  many 
points  along  the  mountain  ranges  in  Laramie  County.  It  has  recently 
been  mined  to  some  extent  at  Whalen  Canon,  20  miles  north  of 
Fort  Laramie,  and  some  of  the  product  has  been  shipped  to  the 
Eastern  market. 

In  New  Mexico  mica  has  been  mined  near  Las  Vegas  and 
Petaca.  In  California  many  deposits  of  mica  have  been  noted, 
especially  at  Gold  Lake,  Plumas  County;  in  Eldorado  County; 
Ivanpah  district,  San  Bernardino  County;  near  Susan ville,  Las- 
sen  County,  and  at  Tehachapi  pass,  Kern  County.  In  1883  a 
large  deposit  was  discovered  in  the  Salmon  Mountains,  in 


SILICATES.  173 

the  northwestern  part  of  the  State,  and  some  prospecting  was 
done.1 

The  mica-bearing  deposits  of  the  Black  Hills  of  South  Dakota 
have  been  variously  regarded  by  observers  as  intrusive  granites 
or  true  segregation  veins  lying  parallel  to  the  apparent  bedding. 
Newton  and  Jenny,2  Blake,3  and  Vincent  regarded  them  as  intrusive, 
while  Carpenter  4  and  Crosby  5  held  the  opposite  view. 

According  to  Blake  the  mica  occurs  in  granitic  masses,  remark- 
able for  the  coarseness  of  their  crystallization,  the  constituent  min- 
erals being  usually  large  and  separately  segregated.  "Large  masses 
of  pure  quartz  are  found  in  one  place  and  masses  of  feldspar  in 
another,  and  the  mica  is  often  accumulated  together  instead  of  being 
regularly  disseminated  through  the  mass.  It  also  occurs  in  large 
masses  or  crystals,  affording  sheets  broad  enough  for  cutting  into 
commercial  sizes."  Associated  with  the  mica  at  this  point  are  the 
minerals  quartz  and  feldspar,  mainly  a  lamellar  albite  (Clevelandite), 
which  form  the  gangue,  and  irregularly  disseminated  cassiterite 
(tinstone),  gigantic  spodumenes,  black  tourmalines,  and,  in  small 
quantities,  black  mica,  beryls,  garnets,  columbite,  and  a  variety  of 
phosphatic  minerals,  such  as  apatite,  triphylite,  etc. 

Sterrett  describes  6  a  mica  deposit  near  Custer  as  occurring  in  a 
pegmatite  intruded  into  gneiss  and  biotite  schist,  dipping  with  the 
country  rock  about  50°  to  the  southwest.  (See  Fig.  29.)  The  intru- 
sive is  about  30  feet  in  thickness  at  the  surface  and  28  feet  at  the 
2oo-foot  level.  The  mica  occurs  in  two  streaks  or  "  veins"  from  i  to  8 
feet  wide,  along  each  wall,  the  middle  portion  being  practically  barren, 
or  at  best  too  poor  to  work.  The  mica  occurs  mostly  in  flattened 
or  tabular  blocks  lying  perpendicular  to  the  walls  and  varying  up  to 
5  inches  in  thickness  and  from  2  to  8  inches  in  diameter.  Crystals 
a  foot  in  diameter  are,  however,  not  rare,  while  some  have  been  found 
of  three  times  that  dimension.  In  certain  portions  of  the  pegmatite 

1  Mineral  Resources  of  the  United  States,  1883-84,  p.  911. 

3  Geology  of  the  Black  Hills  of  Dakota,  Monograph,  U.  S.  Geolgoical  Survey,  1880 . 

3  Engineering  and  Mining  Journal,  XXXVI,  1883,  p.  145. 

4  Transactions  of  the  American  Institute  of  Mining  Engineers,  XVII,  1889,  p.  570. 

5  Proceedings  of  the  Boston  Society  of  Natural  History,  XXIII,  1884-88,  p.  488. 
8  Bulletin  No.  380,  U.  S.  Geological  Survey,  1909. 


'74 


THE   NON-METALLIC  MINERALS. 


there  occurs  abundant  black  tourmaline  in  size  up  to  10  inches  in 
diameter,  and  it  is  noteworthy  that  in  these  portions  the  mica  content 
is  poor. 

In  Nevada  mines  have  been  worked  in  the  St.  Thomas  mining 
district,  Lincoln  County,  the  mica  occurring  in  hard,  glassy  quartz 
rock  forming  an  outcrop  some  200  feet  wide  by  600  feet  long  in 
gneiss  and  schists.  At  the  Czarina  Mine,  located  in  May,  1891, 
near  Rioville,  the  mica  occurs  under  similar  conditions.  The 


Mica  gneiss 


FIG.  29. — Generalized  section  of  mica  mine,  near  Custer,  South  Dakota. 
[After  D.  Sterrett,  Bulletin  No.  380,  U.  S.  Geological  Survey.] 

mineral  seems  to  follow  the  division  plane  of  the  stratification,  along 
the  line  or  axis  of  a  fold.  This  line  runs  north  and  south,  slightly  east 
of  north  of  the  main  trend  of  the  range,  thus  running  into  Arizona  a 
few  miles  north  of  Rioville.  In  fact  the  mica  belt  forms  the  boun- 
dary line  between  Nevada  and  Arizona  for  50  miles.  The  mica, 
mostly  small,  is  abundant,  but  marketable  sizes  are  rare,  and  not 
to  be  had  without  a  great  deal  of  hard  work.2 

Merchantable  mica  has  been  reported  on  the  Payette  River  and 
Bear  Creek,  in  the  Coeur  d'Alene  region  of  Idaho,  and  in  Oregon 
and  Alaska.  Also  in  the  Saguenay  district  of  Canada;  in  the  vicinity 
of  Mattawa,  north  of  Ottawa;  in  Ontario  and  in  British  Columbia. 

2  Mineral  Resources  of  the  United  States,  1893,  p.  754. 


SILICATES. 


175 


The  India  mica  mines  occur  in  coarse  intrusive  pegmatitic- 
granite  dikes,  cutting  what  is  known  as  the  newer  gneiss  of 
Singrauli.  At  Inikurti  the  crystals  are  at  times  as  much  as  10  feet 
in  diameter.  Sheets  4  or  5  feet  across  have  been  obtained,  it  is 
stated,  free  from  such  adventitious  inclusions  as  would  spoil  their 
commercial  value. l 

Phlogopite. — The  occurrence  of  the  pearl-gray  mica  phlogopite 
in  commercial  quantities  is  much  more  restricted  and  so  far  as  is  at 
present  known,  is  limited  to  an  area  of  some  520  square  miles  north 
of  Ottawa,  in  the  province  of  Quebec,  Canada,  and  in  the  townships 
of  Burgess,  Lanark,  and  Loughborough,  province  of  Ontario.  The 
deposits  are  closely  associated  with  intrusive  pyroxenic  rocks  which 
penetrate  the  Laurentian  gneisses  and  overlying  crystalline  limestone, 
sometimes  running  parallel  with  the  gneisses  and  again  cutting  across 


-Lake 


General  trend  of  reina 


FIG.  30. — Section  through  Lake  Girard  Mica  Mine,  Quebec,  Canada. 
[After  Cirkel:  Mica,  Occurrence,  Exploitation,  and  Uses.] 

them.    R.  W.  Ells  has  given  2  the  conditions  of  occurrence  as  follows: 


1  Geology  of  India,  2d  ed.,  1895,  p.  34. 
Bulletin  of  the  Geological  Society  of  America,  V,  1894,  p.  484. 


I76 


THE  NON-METALLIC  MINERALS. 


i.  In  pyroxene  intrusive  rocks  which  either  cut  directly 
across  the  strike  of  grayish  or  other  colored  gneisses  or  are 
intruded  along  the  line  of  stratification.  Some  of  these  deposits 
have  been  worked  downward  along  the  contact  with  the  gneiss, 
where  the  mica  is  most  generally  found,  for  250  feet,  as  at  the 
Lake  Girard  Mine  (Fig.  30),  and  irregular  masses  of  pink  calcite 


FIG.  31. — Section  of  vein  in  Baby  Mine,  North  Burgess,  Ontario. 
[After  Cirkel:  Mica,  Occurrence,  Exploitation,  and  Uses.] 

are  abundant.  In  certain  places  apatite  crystals  occur  associated 
with  the  mica,  but  at  other  times  these  are  apparently  wanting. 
As  in  the  case  of  apatite  deposits,  mica  occurring  in  this 
condition  would  apparently  be  found  at  almost  any  workable 
depth. 

In  pyroxene  rocks  near  the  contact  of  cross-dikes  of  diorite- 
or  feldspar,  the  action  of  which  on  the  pyroxene  has  led  to  the  forma- 
tion of  both  mica  and  apatite.  Numerous  instances  of  this  mode 
of  occurrence  are  found,  both  in  the  mines  of  apatite  and  mica, 


SILICATES. 


I77 


the  deposits  of  the  latter  in  certain  areas  being  quite  extensive  and 
the  crystals  of  large  size.     (Fig.  31.) 

3.  In  pyroxene  rock  itself  distinct  from  the  contact  with  the 
gneiss.  In  these  cases  the  mica  crystals,  often  of  large  size  but 
frequently  crushed  or  broken,  apparently  follow  certain  lines  of 
faults  or  fracture.  Some  of  these  deposits  can  be  traced  for  several 
yards,  but  for  the  most  part  are  pockety.  Some  of  these  pyroxene 


[FiG.  32. — Mica-bearing  pyroxene  dike  in  gneiss.     An  illustration  of  pocket  deposits. 
[After  Cirkel:  Mica,  Occurrence,  Exploitation,  and  Uses.] 

masses  are  very  extensive,  as  in  the  case  of  the  Cascade  Mine  on 
the  Gatineau  River  and  elsewhere  in  the  vicinity.  In  these  cases 
calcite  is  rarely  seen  and  apatite  is  almost  entirely  absent.  When 
cut  by  cross-dikes  conditions  for  the  occurrence  of  mica  or  apatite 
should  be  very  favorable. 

4.  Dikes  of  pyroxene,  often  large,  cutting  limestone  through 
which  subsequent  dikes  of  diorite  or  feldspar  have  intruded,  as  in 
Hincks  township.  The  crystals  occurring  in  the  pyroxene  near  to 
the  feldspar  dikes  are  often  of  large  size  and  dark  color,  resembling 
in  this  respect  a  biotite  mica.  (Fig.  33.) 

It  is  stated  by  Dr.  Ells  that  when  the  pyroxene  is  of  a  light  shade 


1 78  THE  NON-METALLIC  MINERALS. 

of  greenish  gray  and  comparatively  soft,  the  mica  is  corre- 
spondingly light  colored  and  clear,  and  in  some  places  almost 
approaches  the  muscovite  in  general  appearance.  As  the  pyrox- 
ene becomes  darker  in  color  and  harder  in  texture,  the  mica 
assumes  a  correspondingly  darker  tint  and  a  brittle  or  harder 
character,  and  in  certain  cases  where  dikes  of  blackish  horn- 
blendic  diorite  are  present  the  mica  also  assumes  a  black  color  as 
well. 

The  principal  areas  at  present  worked  are  in  the  belt  which 
extends  from  North  Burgess,  in  the  province  of  Ontario,  approxi- 
mately along  the  strike  of  the  gneiss  into  the  territory  adjacent  to 
the  Gatineau  and  Lievre. 


FIG.  33. — Mica-bearing  pyroxene  dike  in  limestone.  An  illustration  of  pocket  deposits. 
[After  Cirkel:  Mica,  Occurrence,  Exploitation,  and  Uses.] 

Biotite. — Black  mica  (biotite,  lepidomelane,  etc.)  is  a  much  more 
common  and  widely  distributed  variety  than  the  white,  but  unlike 
the  latter  is  found  not  so  much  in  veins  as  an  original  constituent 
disseminated  in  small  flakes  throughout  the  mass  of  eruptive  and 
metamorphosed  sedimentary  rocks.  The  small  sizes  of  the  sheets, 
their  color,  and  lack  of  transparency  render  the  material,  as  a  rule, 
of  little  value.  In  Renfrew  County,  Canada,  the  mineral  occurs 
in  large  cleavable  masses,  which  yield  beautiful  smoky-black  and 
greenish  sheets  sufficiently  elastic  for  industrial  purposes. 

Lepidolite. — This  variety  of  mica  is  much  more  rare  than  any 
of  the  others  described.  While  in  a  few  instances  it  has  been 
reported  as  accompanying  muscovite  in  certain  granites,  as  those 
of  Elba  and  Schaistausk,  its  common  form  of  occurrence  is  in  the 
coarse  pegmatitic  veins  already  described,  where  if  is  associated 


SILICATES.  179 

with  muscovite,  tourmalines,  and  other  minerals  of  similar  habit. 
As  a  rule  it  is  readily  distinguished  from  other  .micas  by  its  beautiful 
peach-blossom  pink  color,  though  sometimes  colorless  and  to  be 
distinguished  only  by  the  lithia  reaction.1  The  folia  are  thicker 
than  those  of  muscovite  and  of  small  size,  the  usual  form  being 
that  of  a  scaly  granular  aggregate.  At  Auburn,  Maine,  it  is  found 
both  in  this  form  and  forming  a  border  a  half  inch,  more  or  less, 
in  width  about  the  muscovite  folia.  The  more  noted  localities  in 
the  United  States  are  Auburn,  Androscoggin  County;  Hebron,  Paris, 
Rumford,  and  Norway,  Oxford  County,  Maine,  where  it  is  asso- 
ciated with  beautiful  red  and  green  tourmalines  and  other  interest- 
ing minerals;  Chesterfield,  Massachusetts;  Haddam,  Connecticut; 
the  Black  Hills,  South  Dakota;  and  near  San  Diego,  California. 
The  most  noted  foreign  locality  is  Zinnwald,  Saxony,  where  the 
mineral  occurs  in  large  foliated  masses  together  with  quartz  form- 
ing the  gangue  minerals  of  the  tin  veins.  Also  found  in  Moravia. 
(See  further  under  Spodumene,  p.  200.) 

Roscoelite,  Vanadium  mica. — The  name  roscoelite  has  been 
given  to  a  clove-brown  to  greenish,  micacous  mineral  occurring 
in  minute  scales,  stellate  or  fan-shaped  forms,  and  of  a  somewhat 
doubtful  chemical  formula.  It  may  be  mentioned  here  as  a  possible 
future  source  of  vanadium  salts.  On  the  next  page  are  given  the 
results  of  two  analyses  from  a  recent  paper  by  W.  F.  Hillebrand, 
(i)  being  of  material  from  Placerville,  Colorado,  and  (2)  from 
Eldorado  County,  California. 

Occurrence. — The  material  has  been  reported  as  filling  cavities  in 
quartz  at  the  Granite  Creek  gold  mines  near  Coloma,  El  Dorado 
County,  California,  and  in  the  Magnolia  district  of  Colorado.  More 
recently  deposits  of  some  considerable  economic  importance  have 
been  found  near  Placerville  in  San  Miguel  County,  in  the  last-named 
State.  The  roscoelite  is  described  2  as  occurring  as  an  impregna- 
tion in  the  lower  bed  of  what  is  known  as  the  La  Plata  sandstone 
(Jurassic).  The  beds  at  this  point  are  nearly  horizontal,  the  por- 
tion carrying  the  roscoelite  occurring  in  a  nearly  continuous  band 

1  The  mineral  when  moistened  with  hydrochloric  acid  and  held  on  a  wire  in  the 
flame  of  a  lamp  imparts  to  the  flame  a  brilliant  lithia-red  color. 

2  F.  L.  Ransome,  American  Journal  of  Science,  X,  August,  1900. 


i8o 


THE  NON-METALLIC  MINERALS. 


approximately  parallel  to  the  bedding  planes  and  varying  in  thick- 
ness from  a  few  inches  up  to  5  or  6  feet,  the  vanadiferous  portion 
being  readily  distinguished  from  the  prevailing  light-buff  sand- 
stone by  the  greenish  tint  imparted  by  the  roscoelite.  The  vanadif- 
erous zone  is,  however,  quite  irregular,  the  roscoelite  sometimes 
constituting  20  per  cent  of  the  mass  of  the  sandstone  and  from 
this  fading  out  to  nothing.  It  is  often  associated  with  Carnotite 
(see  p.  332). 

ANALYSES   OF    ROSCOELITE,    A   VANADIUM   MICA. 


Constituent. 

Vanadium 
Mica  frrom 
Placerville. 
Colo. 

Roscoelite  from 
Eldorado 
County,  Cali- 
fornia. 

SiO,  

46.06 

4C.I7 

TiO,  

.78 

V2O3  

12.84 

24.01 

Al  O  . 

22  <  ^ 

1  1  <4 

Fe  0 

7-7 

(FeO)  i  60 

cao:::::::::::::::::::: 

BaO 

I  2C 

MeO 

O2 

i  64 

K  O   . 

88d. 

IO  37 

Na  O   . 

22 

Trace 

HjO  at  105° 

I  08 

a,  40 

H  O  at  io5°-3oo°.  .    .    . 

C  I 

b  17 

H  O  above  300°  

^  $6 

100.00 

99.80 

a.  At  100°. 


i.At  1 80°. 


c.  Above  1 80°. 


Uses. — Until  within  a  few  years  almost  the  only  commercial 
use  of  mica  was  in  the  doors  or  windows  of  stoves  and  furnaces, 
the  peepholes  of  furnaces  and  similar  situations  where  transparency 
and  resistance  to  heat  were  essential  qualities.  To  a  less  extent 
it  was  used  in  lanterns,  and,  it  is  said,  in  the  portholes  of  naval  vessels, 
where  the  vibrations  would  demolish  the  less  elastic  glass.  In 
early  days  it  was  used  for  window  panes,  and  is,  in  isolated  cases 
still  so  used  to  some  extent.  For  all  these  purposes  the  white 
variety  muscovite  is  most  suited.  For  use  in  stoves  and  furnaces 
the  mica  is  generally  split  into  plates  varying  from  about  one-eighth 
to  one  sixty-fourth  of  an  inch  in  thickness.  In  preparing  these 
plates  for  market  the  first  step  is  to  cut  them  into  suitable 


SILICATES.  181 

sizes.  Women  are  frequently  employed  in  this  work.  The  cutter 
sits  on  a  special  bench  which  is  provided  with  a  huge  pair  of  shears, 
one  leg  of  which  is  firmly  fixed  to  the  bench  itself,  while  the  movable 
leg  is  within  convenient  grasp. 

There  is  an  enormous  waste  in  the  processes  of  preparation. 
One  hundred  pounds  of  block  mica  will  scarcely  yield  more  than 
about  fifteen  pounds  of  the  cut  material,  and  sometimes  even  less. 
The  proportion  varies,  of  course,  with  different  localities.1 

According  to  J.  H.  Pratt2  the  North  Carolina  mines  yield  from 
i  to  10  per  cent  of  mica,  and  of  this  amount  not  over  10  to  15  per 
cent  will  yield  commercial  sheet  mica.  Selected  blocks  will  some- 
times yield  30  to  40  per  cent,  and  very  rarely  75  per  cent.  Many 
of  the  Western  mines  do  not  yield  more  than  2  or  3  per  cent  of  cut 
mica.  Sterrett  states  that  the  New  York  mine  at  Custer,  South 
Dakota,  averages  about  6.6  per  cent  of  rough  mica.  Cirkel  states  3 
that  under  ordinary  circumstances  the  Canadian  phlogopite  mines 
must  yield  at  least  1,250  pounds  of  trimmed  mica  for  every  100  tons 
of  rock  moved  from  depths  not  exceeding  300  feet,  in  order  to  be 
profitable.  The  percentage  amounts  of  sizes  of  the  trimmed  mica 
is  extremely  variable.  A  fairly  good  average  is  given  as:  50  per 
cent  of  i//x3//;  30  per  cent  of  2//x3//;  10  per  cent  of  2"x4"; 
6  per  cent  of  3"  x  5",  and  4  per  cent  of  4"  x  6"  and  over. 

Mica  being  a  non-conductor  is  of  value  for  insulating  purposes, 
and  since  the  introduction  of  the  present  system  of  generating 
electricity  there  has  arisen  a  considerable  demand  for  it  in  the  con- 
struction of  dynamos  and  electric  motors.  For  these  purposes 
the  mica  must  be  smooth  and  flexible,  as  well  as  free  from  spots 
or  inequalities  of  any  kind.  It  is  stated  that  it  should  be  sufficiently 
fissile  to  split  into  sheets  not  above  three  one-hundredths  inch  in 
thickness,  and  which  may  be  bent  without  cracking  into  a  circle 
of  3  inches  diameter.  Strips  of  various  dimensions  are  used  in 
building  up  the  armatures,  the  more  common  sizes  being  about 
i  inch  wide  by  6  or  8  inches  long.  Muscovite  serves  the  purposes 

1  Engineering  and  Mining  Journal,  LV,  1893,  p.  4. 

2  Mineral  Resources  of  the  United  States,  1904. 

3  Mica,  Its  Occurrence,  Exploitation  and  Uses,  p.  46. 


182  THE  NON-METALLIC  MINERALS. 

well,  but  is  less  used  than  phlogopite,  the  latter  serving  equally 
well,  and  being  less  desirable  for  stoves  and  furnaces.  Black  mica 
would  doubtless  serve  for  many  purposes,  could  it  be  procured 
in  sheets  of  sufficient  size. 

Mica  scraps  such  as  until  within  a  few  years  have  been  thrown 
away  as  worthless  are  now  utilized  by  grinding,  the  product  being 
used  for  a  variety  of  purposes,  noted  below.  The  material  is,  as 
a  rule,  ground  to  five  sizes,  such  as  will  pass  through  sieves  of  80, 
100,  140,  160,  and  200  meshes  to  the  inch,  respectively.  The  prices 
of  the  ground  material  vary  from  5  to  10  cents  a  pound  according 
to  sizes.  Large  quantities  of  ground  mica  are  used  in  the  manu- 
facture of  wall  paper,  in  producing  the  frost  effects  on  Christmas 
cards,  in  stage  scenery,  and  as  a  powder  for  the  hair,  being  sold 
for  the  latter  purposes  under  the  name  of  diamond  powder.  The 
so-called  French  "  silver  molding  "  is  said  to  be  made  from  ground 
mica.  It  is  also  used  as  a  lubricant,  and  as  a  non-conductor  for 
steam  and  water  heating;  in  the  manufacture  of  door-knobs  and 
buttons.  It  is  stated  further  that  owing  to  its  elasticity  it  can  be 
used  as  an  absorbent  for  nitroglycerine,  rendering  explosion  by 
percussion  much  less  likely  to  occur.  Small  amounts  of  inferior 
qualities  are  also  mixed  with  fertilizers  where  it  is  claimed  to  be 
efficacious  in  retaining  moisture.  A  brilliant  and  unalterable 
mica  paint  is  said  to  be  prepared  by  first  lightly  igniting  the  ground 
mica  and  then  boiling  in  hydrochloric  acid,  after  which  it  is  dried 
and  mixed  with  collodion,  and  applied  with  a  brush.  Owing  to 
the  unalterable  nature  of  the  material  under  all  ordinary  conditions, 
and  the  fact  that  it  can  be  readily  colored  and  still  retain  its  bril- 
liancy and  transparency,  the  ground  mica  is  peculiarly  fitted  for 
many  forms  of  decoration.  Much  of  the  ground  material  now 
produced  is  stated  to  be  sent  to  France. 

The  chief  and  indeed  only  use  for  lepidolite  thus  far  developed 
is  in  the  manufacture  of  the  metal  lithium  and  lithia  salts.  For 
possible  uses  of  roscoelite  see  under  Vanadates. 

Prices. — The  total  value  of  the  cut  mica  produced  annually  in 
the  United  States  during  the  past  fifteen  years  has  varied  from  $50,000 
to  over  $360,000,  while  the  value  of  the  imports  has  varied  between 
$5,000  and  $100,000.  During  1901  but  360,000  pounds  of  cut 


SILICATES.  183 

mica  were  produced,  valued  at  $98,859.  During  the  same  period 
there  were  produced  2,171  tons  of  scrap  mica,  valued  at  $19,719. 
Statistics  for  1907  show  1,060,182  pounds  sheet  mica  valued  at 
$349,311,  and  3,025  short  tons  of  scrap,  valued  at  $42,800.  The 
price  of  the  cut  mica,  it  should  be  stated,  varies  with  the  size  of 
the  sheets,  the  larger  naturally  bringing  the  higher  price.  The 
average  price  of  the  cut  mica,  all  sizes,  is  not  far  from  $i  a  pound, 
while  the  scrap  mica  is  worth  perhaps  half  a  cent  a  pound.  The 
dealers'  lists,  as  published,  include  193  sizes,  varying  from  ij  by 
2  inches  up  to  8  by  10  inches,  the  prices  ranging  from  40  cents  to 
$13  a  pound.  For  electrical  work  upward  of  400  patterns  are 
called  for,  the  prices  varying  from  10  cents  to  $2.50  a  pound. 

BIBLIOGRAPHY. 

W.  C.  KERR.     The  Mica  Veins  of  North  Carolina. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  VIII,  1879,  p.  457. 
MERWYN  SMITH.     Mica  Mining  in  India. 

Engineering  and  Mining  Journal,  LXVIII,  1899,  p.  246. 
R.  W.  ELLS.     Bulletin  on  Mica. 

Mineral  Resources  of  Canada,  1904. 
FRITZ  CIRKEL.     Mica,  Its  Occurrence,  Exploitation,  and  Uses. 

Mines  Branch,  Department  of  Interior,  Canada,  1905. 
G.  W.  COLLES.     Mica  and  the  Mica  Industry. 

Journal  of  Franklin  Institute,  CX  and  CXI,  1905-06. 
RALPH  STOKES.     India  Mica  Industry. 

The  Mining  World,  XXIV,  1906,  pp.  606  and  773. 
DOUGLAS  STERRETT.     Investigations  Relating  to  Mica,  etc.,  in  1906. 

Bulletin  No.  315,  U.  S.  Geological  Survey,  1906,  p.  400. 


3.  ASBESTOS. 

The  name  asbestos  in  its  original  sense  includes  only  a  fibrous 
variety  of  the  mineral  amphibole;  hence  it  is  a  normal  metasilicate 
of  calcium  and  magnesium  with  usually  varying  amounts  of  iron  and 
manganese,  and  not  infrequently  smaller  quantities  of  the  alkalies. 
As  is  well  known,  the  amphiboles  crystallize  in  the  monoclinic  system 
in  forms  varying  from  short,  stout  crystals,  like  common  hornblende, 
to  long  columnar  or  even  fibrous  forms,  to  which  the  names  actinolite, 
tremolite,  and  asbestos  are  applied.  The  word  asbestos  is  derived 


1 84  THE  NON-METALLIC  MINERALS. 

from  the  Greek  acrfiecrTos,  signifying  incombustible,  in  allusion  to  its 
fire-proof  qualities.  The  name  amianthus  was  given  it  by  the  Greeks 
and  Romans,  the  word  signifying  undefiled,  and  was  applied  in 
allusion  to  the  fact  that  cloth  made  from  it  could  be  readily  cleansed 
by  throwing  it  into  the  fire.  As  now  used,  this  term  is  properly 
limited  to  fibrous  varieties  of  serpentine.  Owing  to  careless  usage, 
and  in  part  to  ignorance,  the  name  asbestos1  is  now  applied  to  at 
least  four  distinct  minerals,  having  in  common  only  a  fibrous  struc- 
ture and  more  or  less  fire-  and  acid-proof  properties.  These  four 
minerals  are:  First,  true  asbestos;  second,  anthophyllite ;  third, 
fibrous  serpentine  (chrysotile),  and,  fourth,  crocidolite.  The  true 
asbestos  is  of  a  white  or  gray  color,  sometimes  greenish  or  stained 
yellowish  by  iron  oxide.  Its  fibrous  structure  is,  however,  its  most 
marked  characteristic,  the  entire  mass  of  material  as  taken  from 
the  parent  rock  being  susceptible  of  being  shredded  up  into  fine 
fibers  sometimes  several  feet  in  length.  In  the  better  varieties 
the  fibers  are  sufficiently  elastic  to  permit  of  their  being  woven  into 
cloth.  Often,  however,  through  the  effect  of  weathering  or  other 
agencies,  the  fibers  are  brittle  and  suitable  only  for  felts  and  other 
non-conducting  materials.  The  shape  of  an  asbestos  fiber  is,  as  a 
rule,  polygonal  in  outline  and  of  a  quite  uniform  diameter.  Often 
however,  the  fibers  are  splinter-like,  running  into  fine,  needle-like 
points  at  the  extremity.  The  diameters  of  these  fibers  are  quite 
variable,  and,  indeed,  in  many  instances  there  seems  no  practical 
limit  to  the  shredding.  Down  to  a  diameter  of  0.002  mm.  and  some- 
times to  even  o.ooi  mm.  the  fibers  retain  their  uniform  diameter  and 
polygonal  outlines.  Beyond  this,  however,  they  become  splinter- 
like  and  irregular  as  above  noted. 

The  mineral  anthophyllite,  like  amphibole,  occurs  in  both  mas- 
sive, platy,  and  fibrous  forms,  the  latter  being  to  the  unaided  eye 
indistinguishable  from  the  true  asbestos. 

Chemically  this  mineral  is  a  normal  metasilicate  of  magnesia  of  the 
formula  (Mg,Fe)SiO3,  differing,  it  will  be  observed,  from  asbest6s 

1  Also  spelled  asbestus.  The  termination  os  seems  most  desirable  when  the  deri- 
vation of  the  word  is  considered. 


SILICATES  185 

proper  in  containing  no  appreciable  amount  of  lime.  It  further 
differs  in  crystallizing  in  the  orthorhombic  rather  than  the  mono- 
clinic  system,  a  feature  which  is  determinable  only  with  the  aid  of  a 
microscope.  The  shape  and  size  of  the  fibers  are  essentially  the  same 
as  true  asbestos.  The  fibrous  variety  of  serpentine  to  which  the 
name  asbestos  is  commercially  given  is  a  hydrated  metasilicate  of 
magnesia  of  the  formula  H4Mg3Si2O9  with  usually  a  part  of  the 
magnesia  replaced  by  ferrous  iron.  It  differs,  it  will  be  observed, 
from  asbestos  and  anthophyllite  in  carrying  nearly  14  per  cent 
of  combined  water  and  from  the  first  named  in  containing  no  lime. 
This  mineral  is  in  most  cases  readily  distinguished  from  either  of  the 
others  by  its  soft,  silk-like  fibers  and  further  by  the  fact  that  it  is 
more  or  less  decomposed  by  acids.  As  found  in  nature  the  material 
is  of  a  lively  oil- yellow  or  greenish  color,  compact  and  quite  hard, 
but  may  be  readily  reduced  to  the  white,  fluffy,  fibrous  state  by 
beating,  hand-picking,  or  running  between  roller;  The  length  of 
the  fiber  is  quite  variable,  rarely  exceeding  6  inches,  but  of  very 
smooth,  uniform  diameter  and  great  flexibility. 

The  mineral  crocidolite,  although  somewhat  resembling  fibrous 
serpentine,  belongs  properly  to  the  amphibole  group.  Chemically 
it  is  anhydrous  silicate  of  iron  and  soda,  the  iron  existing  in  both 
the  sesquioxide  and  protoxide  states.  More  or  less  lime  and  magnesia 
may  be  present  as  combined  impurities.  The  color  varies  from  lav- 
ender-blue to  greenish,  the  fibers  being  silky  like  serpentine,  but  with 
a  slightly  harsh  feeling.  The  composition  of  representative  speci- 
mens of  these  minerals  from  various  sources  is  given  in  the  accom- 
panying table.1  (See  pp.  186,  187.) 

Mode  of  occurrence  and  origin. — Concerning  the  associations, 
occurrence,  and  origin  of  the  fibrous  structure  of  these  minerals 
existing  literature  is  strangely  silent.  It  is  known  that  all  occur 
in  regions  occupied  by  the  older  eruptive  and  metamorphic  rocks. 
It  is  probable  that  in  the  fibrous  forms  the  mineral  is  always  secondary, 
and  in  the  true  (amphibole)  asbestos  due  in  part,  at  least,  to  shearing 

1  From  Notes  on  Asbestos  and  Asbestiform  Minerals,  by  George  P.  Merrill.  Pro- 
ceedings of  the  U.  S.  National  Museum,  XVIII,  1895,  PP-  281-292. 


186 


THE  NON-METALLIC  MINERALS. 


5 

Authority 

T3       ^ 

1  1 

o     .  ^ 

rt  o^      oo 

^^p;  r 
J    8 

«     0 

^ 

"E     r'H        r,^ 
J      o^         d^  d 

pi      OP=n'          OpiO 

.S.S'S 

Kffi 

So 

| 

0                     M     M              M     W 

.     0-  dd     dd 

c        c  c     c  "c 
Q        SS    SS 

J 

10  r- 

Tj-          0     M     N              M     10, 

3 

o   •  o      o  o 

0-0         00 

0  0 

o  o 

O,  O  OOO          OCC    O-  O 

00  00   O   O 

00    Ov 

d      odd      o  o 
o      o  o  o      o  o 

c 

$£%    ^S? 

M    10 

3332    £55  3 

0   ro  P»   ro 

00   <*} 

Tj-            M        •        .              O        • 

M    M 

N          O      •      •          ^0     - 

rj 

<-- 

00 

Tj-        •         •                   •         - 

I 

Q   .  Q      o  e 

o  a 

•  o  o  o      e  o   •  o 

55    '     ' 

55 

:    -  :  :     :  : 

s 

/-N    ^"x-N           /-Vx^> 

55 

<t/a"t?'a'    /e"o    i"? 

55  •  • 

9^- 

;     '.  \H     '.  '. 

§ 

d 

G 

Hi  !J 

:|i:    |::| 

•      •      -00 

|| 

rf>     •   M          O     • 
•         0-0         •*    '• 

. 

V 

M 

i 

000  r-      000 

000 

O  Tf  <M    N          00    O  O  00 

00  00    t-  10 

00 

00         O    PO  M           ^    <M 

& 

4) 

§ 

M 

§ 

•  O  ^       O  00 
•  O£H        O  O 

H   ' 

•*  M  00      •         OOO   f^-00 

t^>  ^    *  O 

Ot- 

*?    ^^^     Tt 

B 

MOOI              «)" 

w 

pq 

6 
£ 

roo  0             w-, 

0^  tOO          *«0000 

M        •  00    10 

*:*: 

*?    1"??    ^°. 

"   J    0 

•   • 

M     M 

•     M 

<j 

•        '        •             M        • 

M    10 

.        .        .              CO       • 

0 

I 

:  :  :j      : 

d  ^ 

I  :  :  :  :     :  :  :  : 


*  ; 

:     :  :  :    "2  : 

C/3 

c5 

TO  <N    t-          000 

M     Tj-^t^            M     NO     N 

.    .    .  Tt- 

10 

M   rt- 

•  oo    •       o   • 

W 

^ 

:  : 

0     M     M'     M             M     d     M     ^ 

:  :  :  M' 

M'  0 

•  o    •      o  • 

s 

0 

22X    55 

0   0 
O  t^ 

§10O     M            O  O     M  \O 
l^io  CO        N   OOOO 

O    M    O  00 
t^  ^  1O  O 

R2. 

O        OOO  to       >o  O 
N        O   O  f*-        *<fOO 

CO 

10  10  10          10  10 

1O  1O 

10101010          1010V010 

10  10  10  10 

10  10 

10          10  10  10          •*  >0 

t        ^ 

O  10  10  10 

10    *     -10 

1O  l^- 

w|l| 

OOOO        00 

O  0 

OOOO        1     1     1     1 
OOOO 

1    •   •  1 

0     •     •  0 

1    1 

O  O 

|| 

i: 

,c  : 

Q)   CO 

-32 

.     .     .     .X!  M     .     .     . 

| 

i||| 

11 

o   •  d  d      d  d 

o  o 

13  -a 

B 

$33$ 

I 

o  o-s  <§  d  d      o*  d 
S_ca^'d'T:3     ^^ 

.5     ;   :^ 

<s~;  i 

3  \& 

|  ;  ;  ; 

:     :  :"i     : 

Locality. 

Sails  Mountain,  Geor 

Nacoochee  ,  Ga  
Rabun  Co.  Ga  

Tallapoosa  Co.,  Ala. 
Lenoir.  Caldwell  Co.. 

Warrenton,  Warren 
N.C  
Franklin,  N.C  

~   O  r-  v  «3         ?rS  t-T 

0>  4J  C  •  r<   g         O  o  <D 

,c  t-  oQ  c     •g  e  -1-1 

Pylesville,  Harford 
Md  
Aston,  Delaware  Co  , 
Staten  Island,  New  } 
Zillerthal,  Tyrol  

Cow  Flats,  Bathurst 
South  Wales  
Corsica  
Zillerthal  

Frankenstein,  Silesia 

Cunsdorf,  Saxony.  . 
Taberg,  Sweden.  .  .  . 
'Cow  Flats,  New  J 
Wales  
iBolton  Mass  

i 

SILICATES. 


187 


* 


;§  -d       '£ 

^  1       £ 

^  d  do          g  6s 

K-d  -d-d        £•«-• 


Jrfjf 

5|d     ^                        H      o 

Moo   a              ^o 

| 
i 

0        0 

OOi        HIOOOO             \of00j                   t- 

I 

<og8 

000         OOvOvO              000                   00 

oo      oo      oo          ooo               o 

rO 

0 

toco  r- 

00                    10   H 
00    ?*J          ^                 M^                  MIOIO                       OO 

tl 
* 

^ 

•  •>*• 

•*  M         00    ro 
vO     •         0   o'         0   0                 ...                     o 

1 

•     •        \O  00         t^  O                ... 

s 

.        .              M     M              -.J-Tt-                        ...                               M 

03 

:  : 

••0000                 ...                    0 

§ 

|  | 

•   •      o'  o'      o  o                              ^ 

4 

5 

10  H         ro  t- 

u 

too  w 

. 

M     M 

WM         'SS           MM                 ?5-!J                       ? 

"§> 

«  o>d 

M              M 

."                       M              M     M                          ... 

3 

«?i 

r^.       r^M        HC«O           oooooo 

•u 

H    H       . 

H        . 

b 

•      •   N 

vO  00         •*  t- 

U 

•       •    M 

O-OOOO              MO                         IH 

o' 

M 

385 

O      •         OO    VO         M    t--                   •      • 

H    •       fo  M       do'            •    •    •  J             • 

°0 

H 

w   ro        tt- 

*> 

izz 

^^           ^           2^                    doH                           * 

s 

££8 

ioo 

O     •          •     •          •     •              OOO                   0 

A 

:  :  : 

|i|l.     .ill.     sl^ 

•d 

:  :  : 

lit  j]]     ;|  i 

1 

;;; 

.  ..3    :^  •  •         •§     • 
:il   1S:J          ;S 

i 

i 

a  '• 

«•: 

gf  8 

2^'S 

III 

;  ,:™  |5  ;|       ;-s 

.    .  »3       o  D    .^3                 -'43      n- 

1  ;|  °»i&     S  s 

3  ;|    ^gl^           -.3     § 

*&  "llli    "il  ? 

?rtS    s-Sw^      «ts  5 
c^So  HcB  ££     c3>  < 

0 

X 
V 

00   0  O 
«  N  fO 

MMfO        ^ftovOt^            OOOi        O 
«*>  fO  "J        «O  <*5        «O  <O              CO  to        ^ 

i88  THE  NON-METALLIC  MINERALS. 

agencies;  that  is,  to  movements  in  the  mass  of  a  rock  whereby  a 
mineral  undergoing  crystallization  would  be  compressed  laterally 
and  drawn  out  along  the  line  of  least  resistance.  It  is  even  probable 
that  the  structure  is  but  an  extreme  development  of  the  prismatic 
cleavage,  due  to  the  shearing  forces. 

The  asbestos  of  Alberene,  in  Albemarle  County,  Virginia,  occurs 
in  thin  platy  masses  along  slickensided  zones  in  the  so-called  soap- 
stone  (altered  pyroxenite)  of  the  region,  the  fibers  always  running 
parallel  with  the  direction  of  the  movement  which  has  taken  place. 
The  same  is  true  of  the  asbestos  found  in  the  magnetite  mines  near 
Blacksburg,  in  Cherokee  County,  South  Carolina,  where  the  fibrous 
structure  is  developed  only  along  shear  zones.  At  Alberton,  Mary- 
land, the  fibrous  anthophyllite  occurs  along  a  slickensided  zone  be- 
tween a  schistose  actinolite  rock  and  a  more  massive  serpentinous 
or  talcose  rock,  which  is  also  presumably  an  eruptive  peridotite  or 
pyroxenite.  The  fibration  here  runs  also  parallel  with  the  direction 
of  movement  as  indicated  by  the  slickensided  surfaces. 

The  Sail  Mountain  (Georgia)  asbestos  is  anthophyllite,  of  a 
grayish-white  color,  though  often  stained  by  iron  oxides.  The 
entire  mass  of  the  material  as  mined  is  made  up  of  groups  of  bundles 
of  more  or  less  radial  fibrous  structure,  the  fibers  tending  to  form 
spherical  bunches,  though,  owing  to  imperfect  development  caused 
by  interference  in  crystallization,  the  radial  structure  is  obscured 
and  the  mass  consists  of  fibrous  sheaves  or  bundles  running  in  all 
directions.  As  mined,  it  is  said  to  consist  of  over  90  per  cent  of 
material  which  can  be  utilized  as  fiber.  Within  an  area  a  little  more 
than  one-half  mile  square,  in  the  vicinity  of  Sail  Mountain,  there  are 
stated  to  be  six  separate  masses  of  this  material,  each  one  roughly 
elliptical  in  shape,  with  their  longer  axes  approximately  parallel  and 
running  north  80°  east.  The  country  rock  is  gneiss,  and  the  asbestos 
itself  is  regarded  by  Diller  l  as  an  altered  igneous  rock.  The 
largest  mass  reported  had  a  length  of  about  75  feet  and  a  maximum 
width  of  50  feet.  It  has  been  mined  to  a  depth  upwards  of  50  feet. 

The  asbestiform  serpentine,  as  noted  elsewhere,  occurs  in  short, 
disconnected  gash  veins  which  traverse  the  massive  rock  of  the 

1  Mineral  Resources  of  the  U.  S.,  1907. 


SILICATES.  189 

same  general  nature  in  every  direction.  These  veins  are  short, 
rarely  more  than  a  few  feet  in  length,  and  it  is  impossible  that  there 
should  have  been  any  appreciable  differential  movement  between 
their  walls.  The  present  writer  has  attempted  to  account  for  these 
on  the  assumption  that  the  vein  cavities  were  formed  by  shrinkage, 
and  the  vein  filling  by  a  process  of  growth  of  the  fibers  from  the  walls 
of  the  cavities  inward.1 

Localities. — As  already  stated  true  amphibole  asbestos  occurs 
only  in  regions  of  eruptive  and  metamorphic  rocks  belonging  to  the 
Archaean  and  Paleozoic  formations.  The  same  is  true  of  anthophyllite. 
Fibrous  serpentine  occurs  sporadically  with  the  massive  forms  of 
the  same  rock  which  is,  so  far  as  known,  almost  invariably  an  altered 
eruptive.2  The  three  forms  are  therefore  likely  to  occur  in  greater 
or  less  abundance  in  any  of  the  States  bordering  along  the  Appa- 
lachian system,  but  are  necessarily  lacking  in  the  great  Interior 
Plains  regions,  recurring  once  more  among  the  crystalline  rocks 
of  the  Western  Cordilleras  and  the  Pacific  coast.  The  principal 
States  from  which  either  the  true  asbestos  or  anthophyllite  has 
been  obtained  in  anything  like  commercial  quantities  are  Massa- 
chusetts, Connecticut,  New  York,  Maryland,  Virginia,  North  Caro- 
lina, South  Carolina,  Georgia,  and  Alabama,  though  it  has  been 
reported  from  other  Eastern  as  well  as  several  of  the  Western  States. 
Fibrous  serpentine  (chrysotile,  or  amianthus)  occurs  in  small  amounts 
at  Deer  Isle,  Maine;  in  northern  Vermont;  at  Easton,  Pennsylvania; 
Montville,  New  Jersey;  the  Grand  Canon  region  of  Arizona;  in 
the  Casper  Mountains  of  Wyoming,  and  in  the  State  of  Washing- 
ton. It  is  known  also  to  occur  in  Newfoundland. 

Asbestiform  serpentine  occurs  in  Canada,  in  an  interrupted  belt 
of  serpentinous  rocks  extending  from  the  Chaudiere  River,  in  Quebec 


1  On  the  Formation  of  Veins  of  Asbestiform  Serpentine.     Bulletin  of  the  Geological 
Society  of  America,  XVI,  1905,  p.  133. 

2  The  Montville,  N.  J.,  occurrence  is  evidently  an  exception,  as  is  also  perhaps 
that    of    the    Grand    Canon  region.     In  the  first-mentioned  instance  the  serpentine 
results  from  the  alteration  of  nodular  masses  of  gray  and  white  pyroxene.     The  veins 
of  fibrous  material  are  here,  as  a  rule,  roughly  parallel  to  the  outer  surfaces  of  these 
nodules.     They  are  small,  and  of  no  commercial  value.     (See  On  the  Serpentine  of 
Montville,  N.  J.     By  Geo.  P.  Merrill,  Proc.  U.  S.  National  Museum,  XI,    1885,  PP- 
105-111.) 


i  go 


THE  NON-METALLIC  MINERALS. 


province,   southwesterly  to   the  Vermont  -line,   and  beyond.     The 
principal  producing  points  thus  far  developed  are  in  the  Thetford 


FIG.  34. — Section  of  asbestos-bearing  rocks,  Thetford,  Canada. 
[After  Cirkel:  Asbestos,  Its  Occurrence,  Exploitation,  and  Uses.] 

and  Black  Lake  area,  which  begins  at  a  point  between  the  towns  of 
St.  Joseph  and  St.  Francis,  and  extends  southwesterly  into  Broughton, 


Pre  Cambrian 
]        1  Palaeozoic 


SCALE  OF  MILES 

FlG.  35. — Map  showing  serpentine  areas  in  Eastern  Townships  of  Quebec. 
[After  Cirkel:  Asbestos,  Its  Occurrence,  Exploitation,  and  Uses.] 

Thetford,  Coleraine,  Wolfestown  and  Ham.     A  second  area  begins 
at  Danville  and  extends  through  Brompton,  Oxford,  Bolton,  and 


SILICATES. 


191 


Potton  to  the  Vermont  line.  This  area  has  as  yet  been  productive 
only  at  Danville.  A  third  area  occurs  on  the  Gaspe  Peninsula. 
At  Thetford  the  serpentine  occurs  in  a  series  of  apparently  discon- 
nected masses  of  comparatively  small  extent  which  are  presumably 
altered  gabbros  or  peridotites  that  were  intruded  into  the  prevailing 
schists.  These  serpentinous  masses  have  been  in  their  turn  intruded 
by  dikes  of  diabase  and  granite.  The  fibrous  material  occurs  in 
the  form  of  short  gash  veins,  evidently  shrinkage  cracks,  which 
traverse  the  massive  rock  in  all  directions.  These  are  at  best  but 
a  few  inches  in  width,  pinching  out  to  mere  knife-like  edges,  and 
cf  but  a  few  feet  in  length.  The  edges  of  two  adjacent  veins  often 
overlap,  but  are  apparently  wholly  disconnected  (see  Fig.  36). 
They  also  cut  one  another 
at  every  conceivable  angle. 
Veins  which  do  not  pinch 
out  to  knife  edges  are 
often  split  up,  or  "frayed 
out"  at  the  ends,  like  a 
ragged  piece  of  cloth. 
They  occur  at  intervals 
of  a  few  inches  to  many 
feet,  the  wider  the  vein 
the  greater  the  intervening  Fl&.  36.— Vertical  section  wall  of  asbestos  pit, 

distance,    as    a  rule.      The  Black  Lake,  Canada. 

vein  material    is  itself  of 

almost  silk  -like  fiber,  though  the  individual  fibers  rarely  extend 
from  wall  to  wall,  but  are  interrupted  by  splinters  and  granules  of 
the  massive  material.  Veins  of  more  than  3  or  4  inches  in  width  are 
rare,  though  6  inches  in  width  has  been  reported. 

The  Vermont  asbestos  is  of  the  same  type  as  the  Canadian.  It 
is  found  near  Eden,  in  Lamoille  County,  and  the  adjacent  town  of 
Lowell,  in  Orleans  County,  in  the  northern  part  of  the  State.  At 
Eden  the  mines  occur  in  the  south  face  of  Belvidere  Mountain,  where 
there  is  a  great  mass  of  serpentine  intruded  between  a  micaceous 
schist  below  and  a  hornblendic  schist  above.  The  serpentine 
occurs  in  the  form  of  bold  escarpments,  and  the  mining  is  carried 
on  wholly  from  open  cuts.  The  veins  are  rarely  more  than  three- 


I Q2  THE  NON-METALLIC  MINERALS. 

fourths  of  an  inch  in  width.  At  Lowell  two  types  of  material  are 
met  with,  the  one  with  fibers  standing  practically  at  right  angles  with 
the  walls,  as  in  the  localities  described,  and  the  other  with  fibers 
parallel  to  the  slickensided  faces  of  joints.  This  last  variety  is 
much  the  more  brittle,  and  as  it  occurs  in  layers  seldom  more  than 
an  inch  in  thickness,  is  less  desirable. 

According  to  Pratt,  the  serpentine  asbestos  of  the  Grand  Canon 
region  is  exposed  only  in  the  canon  wall  in  Coconino  County,  Arizona, 


FlG.  37. — Serpentine  asbestos  in  massive  serpentine. 
[  U.  S.  National  Museum.] 


The  material  is  found  in  a  serpentinized  limestone  belonging  to  the 
Algonkian  series,  where,  in  contact  with  intrusive  sheets  of  basalt, 
the  serpentinized  areas  are  almost  constant  over  an  area  of  some 
9,000  feet  in  length,  but  only  from  18  to  24  inches  in  thickness.  The 
asbestiform  seams  are  quite  regular,  varying  in  width  up  to  3 
inches,  the  fibers  being  at  times  of  a  most  beautiful  golden  color, 
and  remarkably  soft  and  silky.  The  smaller  seams  yield  the  highest 


SILICATES.  193 

grade  of  material,  but  the  quality  as  a  whole  is  very  high,  as  good  as 
that  of  Canada,  or  elsewhere. 

The  veins  lie  nearly  5,000  feet  below  the  rim  of  the  Canon,  and 
within  the  area  of  the  National  reservation. 

The  Italian  asbestos  which  finds  its  way  to  the  American  markets 
is  both  of  the  amphibolic  and  serpentinous  varieties,  both  being  re- 
markable for  the  beautiful  long  fibers  they  yield.  The  amphibolic 
variety,  the  true  asbestos,  comes  from  Mont  Cenis,  and  the  serpen- 
tinous variety  from  Aosta. 

Methods  of  mining  and  preparation. — The  mining  of  asbestos  is 
carried  on  almost  wholly  from  open  cuts  and  shallow  tunnels.  Rarely 
does  it  pay  to  follow  the  material  to  any  great  depth. 

In  the  mining  of  the  Canadian  material  the  rock  is  blasted  out 
and  the  asbestos  separated  from  the  inclosing  rock  by  a  process 
known  as  "  cobbing,"  which  consists  in  breaking  away  the  fibrous 
material  from  the  walls  of  the  vein  or  from  other  foreign  ingredients 
by  means  of  hammers. 

The  cobbed  material  is  separated  into  grades,  according  to 
quality,  which  depends  upon  the  length,  fineness,  and  flexibility  of 
the  fiber.  During  1888  the  finest  grades  brought  prices  varying  from 
$80  to  $110  a  ton.  The  prices  at  times  have  gone  even  higher. 
The  amphibole  asbestos,  on  the  other  hand,  rarely  brings  over  $20 
a  ton. 

Uses. — The  uses  of  asbestos  are  manifold,  and  ever  on  the 
increase.  Among  the  ancient  Greeks  it  was  customary  to  wrap 
the  bodies  of  those  to  be  burned  in  asbestos  cloth,  that  their  ashes 
might  be  kept  intact.  In  the  eighth  century  Charlemagne  is  said 
to  have  used  an  asbestos  tablecloth,  which,  when  the  feast  was  over, 
he  would  throw  into  the  fire,  after  a  time  withdrawing  it  cleaned  but 
unharmed,  greatly  to  the  entertainment  of  his  guests.  The  most 
striking  use  to  which  the  material  is  put  is  the  manufacture  of  fire- 
proof cloths  for  theater  curtains,  for  suits  of  firemen  and  others 
liable  to  exposure  to  great  heat.  It  is  also  used  for  packing  pistons, 
closing  joints  in  cylinder  heads,  and  other  fittings  where  heat,  either 
dry  or  from  steam  and  hot  water,  would  shortly  destroy  a  less  durable 
substance.  For  this  purpose  it  is  used  in  the  form  of  a  yarn,  or  as 
millboard.  The  lower  grades,  in  which  the  fibers  are  short  or 


194  THE  NON-METALLIC  MINERALS. 

brittle,  are  made  into  a  felt  which,  on  account  of  its  non-conducting 
powers,  is  utilized  in  covering  steam  boilers.  It  is  also  ground 
and  made  into  cements  and  paints,  the  cement  being  used  as  a  non- 
conductor on  boilers,  and  the  paint  to  render  wooden  structures 
less  susceptible  to  fire.  In  the  chemical  laboratory  the  finely  fibered, 
thoroughly  purified  asbestos  forms  an  indispensable  filtering  medium. 
For  this  purpose  the  true  asbestos  is  preferable  to  the  fibrous  serpen- 
tine. *  In  the  manufacture  of  cloth,  rope,  and  other  materials  where 
strength  and  flexibility  of  fiber  are  essential  the  serpentine  asbestos 
(chrysotile)  is  preferable  to  the  amphibolic  form,  though,  owing  to  its 
hydrous  condition,  it  is,  in  reality  less  fire-proof. 

Within  a  few  years  it  has  been  found  that  the  massive  material 
previously  considered  as  waste  at  the  mines  could,  by  proper  treat- 
ment, be  reduced  to  a  fibrous  pulp  admirably  adapted  for  a  wall 
plaster,  and  similar  uses.  This  material  is  known  under  the  com- 
mercial name  of  asbestic. 

The  chief  use  of  asbestos  is  based  upon  its  highly  refractory  or 
non-combustible  nature.  The  popular  impression  that  it  is  a  non- 
conductor of  heat  is,  according  to  Professor  Donald,  erroneous,  the 
non-conducting  character  of  the  prepared  material  being  due  rather 
to  its  porous  nature  than  to  the  physical  properties  of  the  mineral 
itself.2  Owing  to  the  comparatively  high  price  of  asbestos,  it  is,  in 
the  manufacture  of  the  so-called  non-conducting  materials,  largely 
admixed  with  plaster  of  Paris,  powdered  limestone,  dolomite,  mag- 
nesite,  diatomaceous  earth,  or  carbonaceous  matter,  as  hair,  paper, 
sawdust,  etc.  With  the  possible  exception  of  the  magnesite  (carbon- 
ate of  magnesia)  these  are  all  less  effective  than  the  asbestos,  and 
deteriorate  as  well  as  cheapen  the  manufactured  article.  The 
following  table  will  serve  to  convey  some  idea  of  the  relative  portions 
of  the  various  materials  used  as  non-conducting  pipe  coverings, 
etc.: 


1  Prof.  A.  H.  Chester:  Some  Misconceptions  Concerning  Asbestos.     Engineering 
and  Mining  Journal,  LV,  1893,  p.  531. 

2  The  Mineral  Industry,  II,  1893,  p.  4. 


SILICATES.  195 

Parts. 
Asbestos  sponge,  molded: 

Plaster  of  Paris .. 95.80 

Fibrous  asbestos 4.20 

100.00 
Fire-felt  sectional  covering: 

Asbestos .* ..,..«« 82.00 

Carbonaceous  matter  (hair,  paper,  sawdust,  etc.) •.. .-. 18.00 

100.00 

Magnesia  sectional  covering: 

Carbonate  of  magnesia 92 .20 

Fibrous  asbestos .  .  ... ... ... . . . 7 -80 

100.00 


Magnesia  plastic: 

Carbonate  of  magnesia 92.20 

Fibrous  asbestos 7.80 


100.00 


Asbestos  cement  felting: 

Powdered  limestone 64.50 

Plaster  of  Paris 3.50 

Asbestos 32.00 

100.00 

Asbestos-sponge  cement  felting: 

Powdered  limestone , 59-oo 

Plaster  of  Paris 10.00 

Asbestos 3  i.oo 

100.00 

Fossil  meal: 

Insoluble  silicate 75-°° 

Carbonaceous  matter  (hair,  paper,  sawdust,  etc.) 11.00 

Soluble  mineral  matter 8.00 

Moisture 6.00 


At  Phillipsburg,  New  Jersey,  and  the  adjoining  town  of  Easton, 
Pennsylvania,  a  mineral  pulp  is  prepared  from  a  metamorphic  rock 
of  somewhat  mixed  composition,  occurring  in  the  immediate  vicinity. 
As  quarried,  the  material  is  hard,  compact  and  massive,  Chough 
with  a  somewhat  fibrous  structure,  and  of  a  gray  white  or  greenish 


ig6 


THE    NON-METALLIC  MINERALS. 


color,  the  variation  in  color  being  due  to  the  different  stages  of 
alteration  which  the  rock  has  undergone.  The  least  altered  material, 
of  a  white  or  gray  color,  consists  essentially  of  the  mineral  tremolite, 
which,  as  the  writer  has  elsewhere  l  noted,  undergoes  alteration  into 
serpentine,  giving  rise  to  the  green  color  above  noted.  According  to 
Professor  F.  P.  Peck,2  the  tremolite  at  times  also  undergoes  an  altera- 
tion into  talc.  The  unaltered  tremolite  has  the  following  composition : 


Constituents. 

Per  cent. 

Silica,            SiO2  
Alumina        A12O3  
Manganese,  MnO  
Lime,            CaO   

58.27 

°-33 
0.08 

II    QO 

Magnesia,     MgO  

2C     Q3 

Potash,          K2O  

o  42 

Soda              Na2O 

I     2? 

Water,           H2O 

I     22 

99-40 

The  massive  serpentinous  rock  resulting  from  its  alteration,  and 
which  is  used  in  the  manufacture  of  the  better  grades  of  pulp,  has 
the  following  composition: 


Constituents. 

Per  cent. 

Silica              SiO2 

4C  .  23 

Aluminum  A12O3  

\           <o 

Iron              Fe2O3     

>     2.68 

Lime            CaO  

1.41 

Magnesia,    MgO  

38.34 

Loss  on  ignition 

12     ^O 

99.96 

The  material  is  ground  between  French  buhrstones  and  is  used 
in  the  manufacture  of  rubber  goods  and  as  a  filler  in  paper  manu- 
facture. The  ground  pulp,  at  the  mills,  was  quoted  in  1904  as  worth 
$6.50  per  ton. 


1  Proceedings  U.  S.  National  Museum,  XII,  1890,  p.  599. 

2  Annual  Report  State  Geologist  of  New  Jersey,  1904,  p.  163. 


SILICATES.  197 

The  annual  amount  of  asbestos  of  all  kinds  produced  in  the 
United  States  varies  from  600  to  1,000  tons,  valued  at  about  $15  per 
ton.  Some  30,000  tons  of  asbestos  and  asbestic  are  produced  by  the 
Canadian  mines,  a  considerable  proportion  of  which  finds  its  way  into 
American  markets. 

BIBLIOGRAPHY. 

A.  LIVERSIDGE.     Minerals  of  New  South  Wales,  1888,  p.  180.     Gives  list  of  localities. 
J.  T.  DONALD.     Asbestos  in  Canada. 

The  Mineral  Industry,  I,  1892,  p.  30;   also  II,  1893,  p.  37. 
L.  A.  KLEIN.     Notes  on  the  Asbestos  Industry  of  Canada. 

The  Mineral  Industry,  I,  1892,  p.  32. 
RUDOLF  MARLOCH.     Asbestos  in  South  America. 

Engineering  and  Mining  Journal,  LVIII,  1894,  p.  272. 
C.  E.  WILLIS.     The  Asbestos  Fields  of  Port-au-Port,  Newfoundland. 

Engineering  and  Mining  Journal,  LVIII,  1894,  p.  586. 
GEORGE  P.  MERRILL.     Notes  on  Asbestos  and  Other  Asbestiform  Minerals. 

Proceedings  of  the  U.  S.  National  Museum,  XVIII,  1895,  p.  281. 
H.  NELLES  THOMPSON.     Asbestos  Mining  and  Dressing  at  Thetford. 

The  Journal  of  the  Federated  Canadian  Mining  Institute,    1897,  H»  P-  273« 
See  also  the  Canadian  Mining  Review,  XVI,  1897,  p.  126. 
ROBERT  H.  JONES.     Asbestos  and  Asbestic:   Their  Properties,  Occurrence,  and  Use. 

London,   1897,  pp.  368. 

J.  F.  KEMP.     Notes  on  the  occurrence  of  Asbestos  in  Lamoille  and  Orleans  counties, 
Vermont. 

Mineral  Resources  of  the  United  States  for  1900  et  seq. 
GEORGE  P.  MERRILL.     On  the  Formation  of  Veins  of  Asbestiform  Serpentine. 

Bulletin  of  the  Geological  Society  of  America,  XVI,  1905,  p.  113. 
F.  CIRKEL.     Asbestos,  Its  Occurrence,  Exploitation,  and  Uses. 

4.    GARNET. 

The  chemical  composition  of  the  various  minerals  of  the  garnet 
group  is  somewhat  variable,  though  all  are  essentially  silicates  of 
alumina,  lime,  iron,  or  magnesia.  The  more  common  types  are 
the  lime-alumina  garnet  grossularite,  and  the  iron-alumina  garnet 
alamandite.  Other  varieties  of  value  as  minerals  or  as  gems  are 
pyrope,  spessartite,  andradite,  bredbergite,  and  uvarovite. 

The  ordinary  form  of  the  garnet  is  the  regular  12-  or  24-sided 
solid,  the  dodecahedron  and  trapezodedron,  as  shown  in  Fig.  38. 
The  color  is  dull  red  or  brown,  though  in  the  rarer  forms  yellow, 
green,  and  white.  Hardness  from  6.5  to  7.5  of  the  scale. 


198 


THE  NON-METALLIC  MINERALS. 


Occurrence. — Garnets  occur  mainly  in  metamorphic  siliceous 
rocks,  such  as  the  mica  schists  and  gneisses,  and  though  sometimes 
found  in  limestones  and  in  eruptive  rocks,  are  rarely  sufficiently 
abundant  to  be  of  economic  importance.  In  the  gneisses  and  schists, 
however,  they  at  times  preponderate  over  every  other  constituent, 
varying  from  sizes  smaller  than  a  pin's  head  to  masses  of  100  pounds* 
weight,  or  more. 

The  most  important  garnet-producing  regions  of  the  United 
States  are  Roxbury,  Connecticut,  Warren  County,  New  York,  and 
Delaware  County,  Pennsylvania.  At  the  first-named  locality,  the 
garnets  occur  in  a  mica  schist;  in  New  York  they  are  found  in 


FlG.  38. — Outlines  of  garnet  crystals. 

laminated  pockets  scattered  through  beds  of  a  very  compact  horn- 
blende feldspar  rock,  the  size  of  the  pockets  ranging  from  5  or  6 
inches  in  diameter  to  such  as  will  yield  1,000  pounds  or  more.  In 
the  Delaware  County  localities  the  garnets  occur  in  aggregates  of 
small  crystals  in  a  quartzose  gneiss.1 

One  of  the  most  noted  garnet  regions  of  the  world  is  that  near 
Prague,  Bohemia.  According  to  G.  F.  Kunz,2  the  garnets  of  the 
pyrope  variety  are  indigenous  to  an  eruptive  rock  now  changed  to 
serpentine,  and  the  mineral  is  found  "  loose  in  the  soil  or  in  the 
lower  part  of  the  diluvium,  or  embedded  in  a  serpentine  rock.  .  .  . 
In  mining  the  earth  is  cut  down  in  banks  and  only  the  lower  layer 
removed,  and  the  garnets  are  separated  by  washing.  The  earth 


1  The  Mineral  Industry,  V,  1896. 

3  Transactions  of  the  American  Institute  of  Mining  Engineers,  XXI,  1892,  p.  241* 


SILICATES.  199 

is  first  dry-sifted  and  then  washed  in  a  small  jig  consisting  of  a 
sieve  moved  back  and  forth  in  a  tank  of  water." 

According  to  Mr.  D.  B.  Sterrett,  the  garnets  at  Roxbury,  noted 
above,  occur  in  the  form  of  dodecahedrons  of  all  sizes  up  to  an  inch 
and  a  half  in  diameter,  embedded  in  a  mica  schist. 

The  present  quarry  is  situated  upon  a  hilltop  some  three  miles 
outside  of  the  town  of  Roxbury.  Mining  is  done  wholly  by  open 
cuts.  The  rock  is  blasted  out  by  dynamite  and  broken  into  masses 
suitable  for  handling,  which  are  then  raised  from  the  quarry,  dumped 
into  a  gravity  car,  and  run  to  a  crushing  mill.  The  schist  is  soft, 
crushing  easily,  the  garnets  coming  out,  in  large  part,  free  from 
the  matrix  and  unbroken. 

From  the  crusher  pieces  of  all  sizes  up  to  a  hen's  egg  fall  through 
a  chute  and  are  scattered  evenly  over  a  broad  belt,  some  2  feet 
in  width  and  12  or  more  in  length,  over  which  small  streams 
of  water  are  kept  playing  in  order  to  settle  the  dust  and  cleanse 
the  garnets.  On  either  side  of  this  belt  men  are  employed  to  pick 
out  the  garnets,  which  are  placed  upon  a  small  belt  above  moving 
in  the  same  direction.  This  carries  them  to  the  storing  bins,  where 
they  are  run  into  sacks  of  100  pounds'  weight  each  and  shipped. 

The  waste  at  the  quarry  is  very  great,  amounting,  it  is  estimated, 
to  from  one-half  to  three-fourths  of  the  entire  amount  mined. 

Uses. — Aside  from  their  uses  in  the  cheaper  forms  of  jewelry, 
garnets  are  used  for  abrading  purposes  and  mainly  as  a  sand  for 
sawing  and  grinding  stone  or  for  making  sandpaper.  The  material 
is  of  less  value  than  corundum  or  emery,  owing  to  its  inferior  hard- 
ness. The  commercial  value  is  variable,  but  as  prepared  for  market 
it  is  about  2  cents  a  pound. 


5.  ZIRCON. 

This  is  a  silicate  of  zirconium,  ZrSiO4,  =  silica,  32.8  per  cent; 
zirconia,  67.2  per  cent;  specific  gravity,  4.68  to  4.7;  hardness,  7.5; 
colorless,  grayish,  pale  yellow  to  brown  or  reddish  brown.  Ordi- 
narily in  the  form  of  square  prisms  (Fig.  39). 

Zircon  is  a  common  constituent  of  the  older  eruptives  like  granite 


200 


THE  NON-METALLIC  MINERALS. 


and  syenite,  and  also  occurs  in  granular  limestone,  gneiss,  and 
the  schists.  It  is  so  abundant  in  the  elaeolite  syenites  of  Southern 
Norway  as  to  have  given  rise  to  the  varietal  name  Zircon  syenite. 
Although  widespread  as  a  rock  constituent  it  has  been  reported 
in  but  few  instances  in  sufficient  abundance  to  make  it  of  commercial 
value.  Being  hard  and  very  durable  it  resists  to  the  last  ordinary 
atmospheric  agencies,  and  hence  is  to  be  found  in  beds  of  sand, 

gravel,  and  other  debris  resulting  from 
the  decomposition  of  rocks  in  which  it 
primarily  occurs.  It  has  thus  been 
reported  as  found  in  the  alluvial  sands 
in  Ceylon,  in  the  gold  sands  of  the 
Ural  Mountains,  Australia,  and  other 
places.  In  the  United  States  it  occurs 
in  considerable  abundance  in  the  elaeo- 
lite syenite  of  Litchfield,  Maine,  and 

FIG.  39-  —Outlines  of  zircon  crystals.  .        .          .  .         . 

is  also  found  in  other  States  bordering 

along  the  Appalachian  Mountains.     The  most  noted  localities  are  in 
Henderson  and  Buncombe  counties  in  North  Carolina,  whence  several 
tons  have  been  mined  during  the  past  few  years  from  granite  debris. 
Uses. — See  under  Monazite,  p.  298. 

6.    SPODUMENE  AND   PETALITE. 

Spodumene. — This  is  an  aluminum-lithium  silicate  of  the  formula 
LiAl(SiO3)2,  =  silica,  64.5  per  cent;  alumina,  27.4  per  cent;  lithia, 
8.4  per  cent;  in  nature  more  or  less  impure  through  the  presence  of 
small  amounts  of  ferrous  oxide,  lime,  magnesia,  potash,  and  soda. 
Luster,  vitreous  to  pearly;  colors,  white,  gray,  greenish,  yellow,  and 
amethystine  purple,  transparent  to  translucent.  Usual  form  that  of 
flattened  prismatic  crystals,  with  easy  cleavages  parallel  with  the 
faces  of  the  prism.  Also  in  massive  forms.  Crystals  sometimes 
of  enormous  size,  as  noted  below. 

Mode  of  occurrence. — Spodumene  occurs  commonly  in  the  coarse 
granitic  veins  associated  with  other  lithia  minerals,  together  with 
tourmaline,  beryls,  quartz,  feldspar,  and  mica.  The  chief  localities 
as  given  by  Dana  are  as  below: 


FIG.  i. — Large  Spodumene  Crystals  in  Granitic  Rock,  Etta  Mine,  Black  Hills, 

South    Dakota. 
[From  photograph  by  E.  O.  Hovey.] 


FIG.  2. — Soapstone  Quarry,  Nelson  County,  Virginia. 
[After  Thcs.  Watson,  Mineral  Resources  of  Virginia.] 

PLATE   XVIII. 

[Facing  page  200.] 


SILICATES.  201 

"  In  the  United  States,  in  granite  at  Goshen,  Massachusetts, 
associated  at  one  locality  with  blue  tourmaline  and  beryl;  also 
at  Chesterfield,  Chester,  Huntington  (formerly  Norwich),  and 
Sterling,  Massachusetts;  at  Windham,  Maine,  with  garnet  and 
staurolite;  at  Peru  with  beryl,  triphylite,  petalite;  at  Paris,  in 
Oxford  County;  at  Winchester,  New  Hampshire;  at  Erookfield, 
Connecticut,  in  small  grayish  or  greenish-white  individuals  looking 
like  feldspar;  at  Branchville,  Connecticut,  in  a  vein  of  pegmatite, 
with  lithiophilite,  uraninite,  several  manganesian  phosphates;  near 
Stony  Point,  Alexander  County,  North  Carolina,  the  variety  hid- 
denite  in  cavities  in  a  gneissoid  rock  with  beryl  (emerald),  monazite, 
rutile,  allanite,  quartz,  mica;  near  Ballground,  Cherokee  County, 
Georgia;  in  South  Dakota  at  the  Etta  tin  mine  in  Pennington  County, 
in  immense  crystals.  At  Huntington,  Massachusetts,  it  is  associated 
with  triphylite,  mica,  beryl,  and  albite." 

At  the  Etta  tin  mine,  in  the  Black  Hills  of  South  Dakota,  the 
mineral  occurs,  according  to  W.  P.  Blake,  in  sizes  the  magnitude  of 
which  exceeds  all  records.  Crystalline  masses  extend  across  the 
face  of  the  open  cut  from  2  to  6  feet  in  length  and  from  a  few  inches 
to  12  and  1 8  inches  in  diameter.  The  gigantic  crystals  preserve  the 
cleavage  characteristics  and  show  the  common  prismatic  planes. 
The  color  is  lighter  and  is  without  the  delicate  creamy-pink  hue  of  the 
specimens  from  Massachusetts.  It  is  very  hard,  compact,  and  tough 
and  is  difficult  to  break  across  the  grain.  Some  of  the  fragments  are 
translucent.  See  (Plate  XVIII.) 

The  chief  foreign  localities  of  spodumene  are  Uto  in  Sodermanland, 
Sweden,  where  it  is  associated  with  magnetic-iron  ore,  tourmalines, 
quartz,  and  feldspar,  near  Sterzing  and  Lisens,  in  Tyrol;  embedded 
in  granite  at  Killiney  Bay  near  Dublin,  and  at  Peterhead,  Scotland. 

Uses.  — Spodumene  and  the  lithia-mica  lepidolite  are  used  in 
the  manufacture  of  lithia  salts,  although  the  industry  is  not  yet 
one  of  great  importance.  The  price  of  the  crude  material  varies 
with  the  percentage  of  lithium,  which  as  noted  is  greatest  in  the  first- 
named  mineral.  During  the  year  1901  the  prices  ranged  from  $11.00 
to  $40.00  per  ton.  the  total  production  for  the  year  being  but  1,750 
tons,  derived  mainly  from  California  and  in  the  form  of  lepidolite. 

Petalite,  another  lithium-aluminum  silicate   containing  2.5  to 


2O2 


THE  ^ON-METALLIC  M.NERALS. 


5  per  cent  lithia  occurs  associated  with  lepidolite,  tourmaline,  and 
spodumene  in  an  iron  mine  at  Uto,  Sweden,  with  spodumene  and 
albite  at  Peru,  Maine,  and  with  scapolite  at  Bolton,  Massachusetts. 

7.  LAZURITE;   LAPIS  LAZULI;    OR  NATIVE  ULTRAMARINE. 

Composition  essentially  Na4(NaS3.Al)Al2Si3O12,  =  silica,  31.7  per 
cent;  alumina,  26.9  per  cent;  soda,  27.3  per  cent;  sulphur,  16.9 
per  cent;  hardness,  5.5;  specific  gravity,  2.38  to  2.45.  Color,  rich 
azure-violet  or  greenish  blue,  translucent  to  opaque.  The  ordinary 
lapis  lazuli  is  not  a  simple  mineral  as  given  above,  but  a  mixture 
of  lazurite,  hauynite,  and  various  other  minerals. 

The  following  analyses  quoted  from  Dana  serve  to  show  the 
heterogeneous  character  of  the  material  as  found: 


Localities. 

Silica, 
SiO2. 

Alumina, 
A1203. 

Ferric 
Iron. 
Fe203. 

Lime, 
CaO. 

Soda 
Na2O. 

Water, 
H2O. 

Sulphur, 
S03. 

Orient  

4.C.27 

12.'?'? 

2.12 

23.  ">6 

II.  4? 

o.3S 

T..22 

Ditrd 

4O  ^4 

43.OO 

086 

I  14 

1  2  ^4 

I  02 

Andes             .  % 

4.r  70 

2SJ.34 

I.  ^O 

7.48 

jO.C  C 

A      00 

4-0^ 

Occurrence. — The  localities  are  mostly  foreign.  The  ultramarine 
reported  not  long  since  as  occurring  near  Silver  City,  New  Mexico, 
has  been  shown  by  R.  L.  Packard  to  be  a  magnesian  silicate. 

Mexico,  Chile,  Siberia,  India,  and  Persia  are  the  chief  sources. 
The  following  regarding  the  Indian  localities  is  taken  from  Ball's 
Geology  of  India,  Part  III. 

The  lapis  lazuli  sold  in  Kandahar  is  brought  from  Sadmoneir 
and  Bijour,  where  it  is  said  to  occur  in  masses  and  nodules  embedded 
in  other  rocks.  It  is  also  said  to  have  been  found  at  Hazara,  and 
in  Khelat.  Several  writers  speak  of  its  occurrence  in  Beluchistan, 
but  possibly  this  may  be  due  to  some  confusion  in  names.  Beyond 
a  question  it  does  exist  in  Badaksham,  the  mines  south  of  Firgamu, 
in  the  Kokcha  valley,  having  been  described  by  Wood  in  the  narra- 
tive of  his  journey  to  the  Oxus. 

The  entrance  to  the  mines  is  on  the  face  of  the  mountain  at  an 
elevation  of  about  1,500  feet  above  the  level  of  the  stream.  The 
country  rocks  are  veined,  black  and  white  limestones.  The  principal 
mine  as  represented  in  elevation  pursues  a  somewhat  serpentine 


SILICATES.  203 

direction.  The  shaft  by  which  one  descends  to  the  gallery  is  about 
10  feet  square,  and  30  paces  long,  with  a  gentle  descent,  and  is 
unsupported  by  pillars.  Fires  are  used  to  soften  the  rock  and  cause 
it  to  crack;  on  being  hammered  it  comes  off  in  flakes,  and  when  the 
precious  stone  is  disclosed  a  groove  is  picked  round  it,  and  together 
with  the  portion  of  the  matrix  it  is  pried  out  by  means  of  crowbars. 
Three  varieties  are  distinguished  by  the  miners,  the  nili,  or  indigo 
colored,  the  asmani,  or  sky-blue,  and  the  sabzi,  or  green.  The  labor 
is  compulsory,  and  mining  was  only  practiced  in  the  winter.  Ac- 
cording to  Wood,  these  mines  and  also  those  for  rubies  had  not  been 
worked  for  years,  as  they  had  ceased  to  be  profitable.  Formerly  the 
produce  from  these  mines,  which  must  have  been  considerable,  was 
exported  principally  to  Bokhara  and  China,  whence  a  portion  found 
its  way  to  Europe. 

Marco  Polo  states  that  the  azure  found  here  was  the  finest  in  the 
world,  and  that  it  occurred  in  a  vein.  The  Yamgan  tract,  in  which 
the  mines  were  situated,  contained  many  other  mines,  and  doubtless 
Tavernier  referred  to  it  when  he  spoke  of  the  territory  of  a  Raja 
beyond  Kashmir  and  toward  Thibet,  where  there  were  three  moun- 
tains close  to  one  another,  one  of  which  produced  gold,  another 
granats  (garnets,  or  rather  balas  rubies),  and  the  third  lapis  lazuli. 

A  small  quantity  of  the  mineral  is  said  to  be  imported  into  the 
Punjab  from  Kashgar,  and  a.  mine  is  reported  to  exist  near  the 
source  of  the  Koultouk,  a  river  which  falls  into  Lake  Baikal. 

Uses. — Ultramarine  for  coloring  purposes  has  in  modern  times 
lost  much  of  its  value,  owing  to  the  discovery  by  M.  Guimet  in 
1828  of  an  artificial  substitute.  Formerly  it  was  much  used  as  a 
pigment,  being  preferred  by  artists  in  consequence  of  its  possessing 
greater  purity  and  clearness  of  tint.  According  to  Ball,1  the  artificial 
substitute  is  now  commonly  sold  in  the  bazars  of  India  under  the 
same  name,  lajward,  for  about  4  rupees  a  seer,  while  at  Kandahar 
in  the  year  1841,  according  to  Captain  Hutton,  the  true  lajward, 
which  was  used  for  house  painting  and  book  illuminating,  was  sold, 
when  purified,  at  from  80  to  100  rupees  a  seer.  Mr.  Emanuel 
states  that  the  value  of  the  stone  itself,  when  of  good  color,  varies, 
according  to  size,  from  10  to  50  shillings  an  ounce.  In  Europe  the 

1  Geology  of  India,  III,  p.  528. 


204 


THE  NON-METALLIC  MINERALS. 


refuse  in  the  manufacture  is  calcined,  and  affords  delicate  gray 
pigments,  which  are  known  as  ultramarine  ash. 

La j  ward  is  prescribed  internally  as  a  medicine  by  native  phy- 
sicians; it  has  been  applied  externally  to  ulcers.  That  it  possesses 
any  real  therapeutic  powers  is,  of  course,  doubtful. 

Although  no  longer  a  source  of  any  considerable  amount  of  the 
ultramarine  of  commerce,  the  compact  varieties  of  the  mineral,  such 
as  that  from  Persia,  are  highly  esteemed  for  the  manufacture  of 
mosaics,  vases,  and  other  small  ornaments. 

8.  ALLANITE;  ORTHITE. 

This  is  a  cerium  epidote  of  the  formula  HRIIRIII3Si3O13,  in  which 
R11  may  be  either  calcium  or  iron  (or  both)  and  R111  aluminum,  iron 
cerium,  didymium,  or  lanthanum.  The  analyses  given  below  are 
selected  from  Dana's  Mineralogy  as  showing  variation  in  the  com- 
position sufficient  for  present  purposes : 


Constituents. 

I. 

II. 

III. 

Silica  (SiO2)                   

31.63 

33.03 

30.04. 

Thoria  (ThO2)                            

ox-"o 

0.87 

1.  12 

None. 

Alumina  (A12O3)  . 

13.21 

17.63 

16  10 

Iron  sesquioxide  (Fe  O  ) 

8.30 

c;.26 

S  06 

Cerium  sesquioxide  (Ce  O») 

8.6? 

o-*^ 
2.84 

1  1  61 

Didymium.  sesquioxide  (Di,CX)  . 

<.6o 

7.68 

530 

Lanthanum  sesquioxide  (La2O,>)  

5«w 

<.4.6 

None. 

411 

Yttrium  sesquioxide  (Y.CX)  ...... 

0.87 

2.Q2 

None. 

Erbinum  sesquioxide  (Er,Oo)  

0.^2 

None. 

None. 

Iron  protoxide  (FeO)  

7.86 

7.01 

0.80 

Manganese  (IVInO)            

1.66 

0.64 

Trace. 

Lime  (CaO)  

10.48 

12.78 

13.02 

o  08 

on 

in 

Potash  (K  O) 

o  28 

O  4.O 

o  02 

Soda  (Na  O) 

None 

None 

o  28 

Water  (HO).                           

•2  4.0 

0  37 

2  «;6 

99.07 

100.79 

99.19 

(I)  Hittero,  Norway;   (II)  Ytterby,  Sweden;   (III)  Nelson  County,  Virginia. 

When  in  crystals  often  in  long  slender  nail-like  forms  (orthite) ; 
also  massive  and  in  embedded  granules.  Color,  pitch-black,  brown- 
ish, and  yellow.  Brittle.  Hardness,  5.5  to  6.  Specific  gravity,  3.5 
to  4.2.  Before  the  blowpipe  it  fuses  and  swells  up  to  a  dark,  slaggy, 
magnetic  glass. 

Localities  and  mode  of  occurrence. — The  more  common  occur- 


SILICATES. 


205 


rence  is  in  the  form  of  small,  acicular  crystals  as  an  original  con- 
stituent in  granitic  rocks.  It  also  occurs  in  white  limestone,  asso- 
ciated with  magnetic-iron  ore,  and  in  igneous  rocks  as  andesite,  diorite, 
and  rhyolite.  At  the  Cook  Iron  Mines,  near  Port  Henry,  New  York, 
it  is  reported  as  occurring  in  great  abundance  and  in  crystals  of 
extraordinary  size,  in  a  gangue  of  quartz  and  orthoclase. 

The  variety  orthite  occurs  in  forms  closely  simulating  rusty 
nails  in  the  granitic  rock  about  Brunswick,  Maine.  In  Arendal, 
Norway,  it  is  found  in  massive  forms.  At  Finbo,  near  Falun, 
Sweden,  in  acicular  crystals  a  foot  or  more  in  length.  In  Amherst 
and  Fauquier  counties,  Virginia,  it  occurs  in  large  masses,  as  it 
also  does  near  Bethany  Church,  Iredell  County,  North  Carolina, 
and  Llano  County,  Texas.  At  Balsam  Gap,  Buncombe  County, 
North  Carolina,  it  occurs  in  slender  crystals  6  to  12  inches  long  and 
in  crystalline  masses,  in  a  granitic  vein  and  under  similar  conditions 
at  the  Buchanan  and  Wiseman  mines  in  Mitchell  County. 

Uses. — See  under  Monazite,  p.  307. 


9.    GADOLINITE. 

This  is  a  basic  orthosilicate  of  yttrium,  iron,  and  glucinum, 
though  with  frequently  varying  amounts  of  didymium,  lanthanum, 
etc.  The  formula  as  given  by  Dana  is  Gl2FeY2Si2O10,  =  silica, 
23.9  per  cent;  yttrium  oxides,  51.8  per  cent;  iron  protoxide,  14.3 
per  cent,  and  glucina,  10  per  cent.  Actual  analyses  yielded  results 
as  below: 


Constituents. 

I. 

II. 

Silica  (SiO,) 

2A    7  C 

2  3  7O 

Thoria  (ThO2)  

O.3.O 

O.itS 

Yttrium  sesquioxide  (Y  CX) 

A?   Q6 

41   c  f 

Cerium  sesquioxide  (Ce  On) 

i  6^ 

2  62 

Didymium  sesquioxide  (Di2O3)  

) 

Lanthanum  sesquioxide  (La  O  ) 

{    3-°6 

5.22 

Iron  sesquioxide  (Fe2O  ) 

2  O3 

o  96 

Iron  protoxide  (FeO)  

II.3Q 

12.42 

Bervlium  (Glucina)  protoxide  (BeO) 

IO  1  7 

II    33 

Lime  (CaO)  

o-  30 

O  74 

Soda  (Na,O)  

V.jV 

O  I  7 

Trace 

Water  (H2O)  

O  C2 

i  03 

99.90 

100.24 

(I)  Ytterby,  near  Stockholm,  Sweden;   (II)   Llano  County,  Texas. 


206  THE  NON-METALLIC  MINERALS. 

The  mineral  is  sometimes  found  in  form  of  rough  and  coarse 
crystals,  but  more  commonly  in  amorphous,  glassy  forms.  Hard- 
ness, 6.5  to  7;  specific  gravity,  4  to  4.47.  Color,  brown,  black,  and 
greenish  black,  usually  translucent  in  thin  splinters  and  of  a  grass- 
green  to  olive-green  color  by  transmitted  light.  No  true  cleavage; 
fracture  conchoidal  or  splintery  like  glass,  and  with  a  vitreous  or 
somewhat  greasy  luster.  Through  oxidation  and  hydration  the 
mineral  becomes  opaque,  brown,  and  earthy.  Hence  masses  are 
not  infrequently  found  consisting  of  the  normal  glassy  gadolinite 
enveloped  in  a  brown- red  crust  of  oxidation  products.  On  casual 
inspection  the  mineral  closely  resembles  samarskite  and  the  dark, 
opaque  varieties  of  orthite,  but  is  easily  distinguished  from  the 
fact  that,  before  the  blowpipe  it  glows  brightly  for  a  moment  and 
then  swells  up,  cracks  open,  and  becomes  greenish  without  fusing. 
Some  varieties  (the  normal  anisotropic  forms)  swell  up  into  cauli- 
flower-like forms  and  fuse  to  a  whitish  mass.  Like  orthite,  it  gives 
a  jelly  when  the  powdered  mineral  is  boiled  in  hydrochloric  acid. 

Localities  and  mode  of  occurrence. — The  mineral  occurs  mainly 
in  coarse  pegmatitic  veins  associated  with  allanite  and  other  allied 
minerals.  The  principal  locality  in  the  United  States  thus  far 
described  is  some  five  miles  south  of  Bluffton  on  the  west  bank 
of  the  Colorado  River,  in  Llano  County,  Texas.  The  region  is 
described  1  as  occupied  by  Archaean  rocks  with  granite,  and  occasional 
cappings  of  limestone. 

A  coarse  deep- red  granite  is  the  most  abundant,  and  is  cut  by 
numerous  extensive  veins  of  quartz  and  feldspar  which  carry  the 
gadolinite,  in  pockety  masses,  and  the  other  minerals  mentioned. 
Most  of  the  mineral  thus  far  found  is  altered  into  the  brown-red 
waxy  material  noted  above  and  occurs  in  the  form  of  masses  weigh- 
ing half  a  pound  and  upward.  One  "huge  pointed  mass,  in  reality 
a  crystal,  weighed  fully  60  pounds";  another,  42  pounds.  One 
of  the  earliest  opened  pockets  yielded  some  500  kilos  (noo  pounds) 
of  the  mineral. 

Of  the  foreign  localities  those  of  Kararfvet,  Broddbo,  and  Finbo, 

1  American  Journal  of  Science,  XXXVIII,  1889,  p.  474.  See  also  Bulletin  No.  340, 
U.  S.  Geological  Survey,  1908,  pp.  286-294. 


SILICATES. 


207 


near  Falun,  Sweden,  and  at  Ytterby,  near  Stockholm,  are  important, 
the  mineral  here  occurring  in  the  form  of  rounded  masses  embedded 
in  a  coarse  granite.  On  the  island  of  Hittero,  in  the  Flecke  fiord, 
Southern  Norway,  crystals  sometimes  four  inches  across  have  been 
obtained. 

Uses. — See  under  Monazite,  p.  307. 

10.  CERITE. 

This  is  a  silicate  of  the  metals  of  the  cerium  group  and  of  a  com- 
plex and  doubtful  formula.  The  analyses  below,  taken  from  Dana's 
System  of  Mineralogy,  will  serve  to  show  the  varying  character 
of  the  mineral. 


Constituents. 

I. 

II. 

III. 

Silica  (SiO2) 

19.18 
64-55 
}    7-28 
i-54 

22.79 
24.06 

35-37 

3-92 
1.26 

18.18 
33-25 
34.60 

3-i8 

Cerium  oxide  (Ce,Oo)  

Didyrnium  oxide  (Di2O~).  .  .. 

Lanthanum  (La2O3)  .   . 

Iron  oxide  (FeO)  

Alumina  (ALO,)  

Lime  (CaO)   

i-3S 

5-71 

4-35 

3-44 

1.69 

5-i8 

Water  (H2O)  

The  mineral  occurs  in  gneiss  and  mica  schist,  and  is  of  a  pre- 
vailing pink  to  gray  color. 

Uses. — See  under  Monazite,  p.  307. 


II.    RHODONITE. 

This  is  a  metasilicate  of  manganese  of  the  formula  MnSiO3, 
=  silica,  45.9  per  cent;  manganese  protoxide,  54.1.  As  a  rule, 
iron,  calcium,  or  zinc  replaces  a  part  of  the  manganese.  The  pre- 
vailing form  of  the  mineral  when  in  crystals  is  that  of  rough,  tabular, 
or  elongated  prisms  with  rounded  edges.  It  is  also  common  in 
massive  highly  cleavable  forms,  and  in  disseminated  granules. 
Rarely,  as  in  the  Ekaterinburg  district  of  Russia,  it  occurs  in  massive 
forms  suitable  for  ornamental  work.  Color,  brownish  red,  flesh- 
red,  and  pink;  sometimes  rose- red.  Hardness,  5.5  to  6.5.  Specific 
gravity,  3.4  to  3.68. 


208  THE  NON-METALLIC  MINERALS. 

On  exposure  the  mineral  undergoes  oxidation,  becoming  coated 
with  a  black  film  and  giving  rise  thus  to  indefinite  admixtures  of 
silicate,  oxides,  and  carbonates  of  manganese. 

The  mineral  occurs  in  abundance  associated  with  the  iron  ores 
of  Wermland,  Sweden,  and  at  other  localities  in  Europe ;  in  Ekaterin- 
burg, Russia,  as  above  noted.  A  vein  of  the  massive  material  was 
discovered  some  years  ago,  near  Waits  River,  Vermont,  and  it  has 
been  reported  as  occurring  near  Sitka,  Alaska.  The  zinciferous 
variety  associated  with  the  zinc  ores  in  granular  limestones  of  Sussex 
County,  New  Jersey,  is  known  as  fowlerite. 

So  far  as  the  writer  has  information,  rhodonite  has  as  yet  little 
commercial  value,  excepting  as  an  ornamental  stone.  To  some 
extent  it  has  been  utilized  in  glazing  pottery  and  as  a  flux  in  smelt- 
ing furnaces. 


12.  STEATITE;   TALC;   AND  SOAPSTONE. 

Steatite,  or  talc,  is  a  soft  micaceous  mineral  of  the  formula 
H2Mg3Si4Oi2,  and  consisting  when  pure  of  63.5  per  cent  of  silica, 
31.7  per  cent  of  magnesia,  and  4.8  per  cent  of  water.  Its  most 
striking  characteristics  are  its  softness,  which  is  such  that  it  can  be 
readily  cut  with  a  knife  or  even  with  the  thumb  nail,  and  soapy 
feeling,  there  being  an  entire  absence  of  anything  like  grit.  The 
prevailing  colors  are  white  or  gray  and  apple-green.  Several  varietal 
forms  are  recognized ;  the  name  talc  a  as  rule  being  applied  to  the  dis- 
tinctly foliaceous  or  micaceous  variety,  while  that  of  steatite  is  re- 
served for  the  compact  cryptocrystalline  to  coarsely  granular 
forms. 

Pyrallolite  and  rensselaerite  are  names  given  to  varietal  forms  of 
talc  resulting  from  the  alteration  of  hornblende  or  pyroxene.  Such 
forms  are  found  in  various  portions  of  northern  New  York,  Canada, 
and  Finland.  According  to  Dana,  a  part  of  the  so-called  agalmatolite 
used  by  the  Chinese  is  steatite. 

The  name  soapstone  is  given  to  dark-gray  and  greenish  talcose 
rocks,  which  are  soft  enough  to  be  roadily  cut  with  a  knife,  and 
which  have  a  pronounced  soapy  or  greasy  feeling;  hence  the  name. 
Such  rocks  are  commonly  stated  in  text-books  to  be  compact  forms 


SILICATES. 


209 


of  steatite,  or  talc,  but  as  the  writer  has  elsewhere  pointed  out,1  and 
as  shown  by  the  analyses  here  given,  few  of  them  are  even  approx- 
imately pure  forms  of  this  mineral,  but  all  contain  varying  propor- 
tions of  chlorite,  mica,  and  tremolite,  together  with  perhaps  unaltered 
residuals  of  pyroxene,  granules  of  iron  ore,  iron  pyrites,  quartz, 
and,  in  seams  and  veins,  calcite  and  magnesian  carbonates. 

Composition. — The   varying   composition   of   talc   is   shown   in 
the  series  of  analyses  given  below: 


ANALYSES  OF  TALC  AND  STEATITE. 


Locality. 

SiO2. 

A1203. 

FeO. 

MgO. 

CaO.|MnO. 

Na2O. 

K20. 

H20. 

Totals. 

100.58 
100  .00 
100  .  07 

100.  OO 
IOO  .  OO 

St.  Lawrence  Co.,  New  York. 
Do 

60.59 

0.13 

0.  21 

34-72 

1.16 

17 

3-77 
2.05 

o  .  60 
Not 
deter- 
min- 
ed. 

Hewitt  Mine,  N.  Carolina.  .  .  . 
Luzenach,  France  

6i.35 

61.85 
60.60 

4.42 

2.61 

o.  30 

1.68 

0.25 
0.60 

26.03 

34.52 
35-30 

0.82 

Trace 
o  .  40 

0.62 

0. 

'2!8o 

Valley  of  Pignerolles,  Italy.  .  . 

The  following  analyses  of  soapstone  have  been  made  in  the 
laboratory  of  the  U.  S.  National  Museum: 


ANALYSES  OF  SOAPSTONE. 


Locality. 

Si02. 

A1203. 

FeO. 

MgO. 

CaO. 

MnO. 

NagO. 

K2O. 

H2O. 

Totals. 
99-4^ 

I  00  .  05 

99.88 
100.03 
99-93 
99-57 

Francestown,  New  Hampshire 
Grafton  Vermont 

42.43 

51  .  20 
38.37 
52.70 
40.03 

33-47 

6.08 

5-  22 

5.64 

5-57 
10.86 
0-45 

13-07 
8.45 
8.86 
7-63 
9-59 
7.38 

25-71 
26.79 
28.62 
26.88 
26.97 
33-72 

3-27 
i  .17 
3-90 
1-77 
1.70 
1-34 

Trace 
0.32 

Trace 

0.  21 

o   16 

o  32 

8.45 
6.  90 
14.49 
5.48 
ro.  78 
23-00 

Dana,  Massachusetts  
Baltimore  County,  Maryland. 
Guilford  Co.  .  North  Carolina  . 
Lafayette  ,  Pennsylvania  

Occurrence  and  origin. — Talc  in  all  its  forms  is  presumably 
always  a  secondary  mineral,  a  product  of  alteration  of  other  mag- 
nesian silicates.  If  resulting  from  the  alteration  of  a  pure  enstatite, 
the  process  might  be  illustrated  as  follows:  4(MgSi)O12  +  H2O  + 
=  H2Mg3Si4O12  +  MgCO3,  or,  if  from  tremolite,  as  follows: 
i4O12+H2O  +  CO2  =  H2Mg3Si4O12  +  CaCO3.  In  the  large 
majority  of  cases  it  is  safe  to  assume  that  the  alteration  is  from  min- 
erals carrying  more  or  less  alumina  and  iron,  in  which  case  the  latter 
may  separate  out  as  an  oxide  or  may  remain,  replacing  a  portion  of 


1  Rocks,  Rockweathering,  and  Soils,  2d  ed.,  p.  95. 


210  THE  NON-METALLIC  MINERALS. 

the   lime  or  magnesia,   in   any  case    a    less    pure  variety  of    talc 
resulting. 

New  York. — Talc  in  quantities  sufficient  to  be  of  commercial 
importance  occurs  in  beds  intercalated  in  schistose  Azoic  limestones 
in  the  towns  of  Edwards  and  Fowler,  near  Gouverneur  in  St.  Law- 
rence County.  The  beds  dip  with  the  inclosing  rock  at  a  high  angle, 
the  individual  "  veins"  varying  from  a  few  inches  to  20  feet  in  width. 
The  mineral,  which  is  regarded  by  Smyth  l  as  an  alteration  product 
of  schistose  aggregates  of  enstatite,  or  perhaps  tremolite,  is  mainly 
in  the  form  known  as  agalite  and  rensselaerite,  the  one  a  smooth, 
fibrous  variety  and  the  other  foliated  and  lamellar,  either  being  of  a 
beautiful  'white  color.  Masses  of  unaltered  tremolite  still  occur 
imbedded  in  the  talc,  which  also  at  times  carries  a  small  amount  of 
quartz.  These  are  the  largest  and  most  extensively  worked  deposits 
at  present  known  within  the  limits  of  the  United  States. 

Virginia. — Numerous  deposits  of  talc  occur  in  Fairfax  County, 
Virginia,  the  material  being  invariably  associated  with  lenses  of 
dioritic  or  gabbroic  rock  in  such  a  manner  as  to  indicate  that  they 
originated  through  the  alteration  of  the  more  basic,  non-feldspathic 
portions  of  these  intrusives.  The  mineral  is  mainly  in  schistose  and 
somewhat  fibrous  form  and  is  found  in  very  indefinitely  outlined 
lenses  extending  with  their  longer  axes  in  a  northeast-southwest 
direction  conforming  closely  with  the  general  strike  and  dip  of  the 
inclosing  rock.  The  lenses  or  pockets  of  commercial  material  are 
of  comparatively  limited  extent,  but  a  few  feet  in  width,  though  they 
may  be  reaching  to  a  depth  beyond  practical  mining.  The  bodies 
of  good,  gritless  material  wedge  out,  often  quite  abruptly,  and  be- 
come interleaved  with  harder,  amphibolic  and  chloritic  minerals, 
wholly  without  discernable  law  or  system.  Small  cross  veins  some- 
times occur,  which  are  filled  with  light-green,  foliated  talc.  Such 
are,  however,  too  small  to  be  taken  into  account  in  working. 

The  mining  is  carried  on  by  a  system  of  comparatively  shallow 
open  trenches  which  are  abandoned  when  through  the  presence  of 
water  or  deterioration  of  product  they  became  unprofitable.  The 
material  found  near  Wiehle  and  Hunter's  Station  is  used  largely  in 
foundry  work. 

1  Fifteenth  Annual  Report  of  the  State  Geologist  of  New  York,  1895. 


SILICATES.  2il 

The  Carolinas. — In  western  North  Carolina  and  northern  Georgia, 
particularly  in  Cherokee  and  Swain  counties  in  the  first-named  State, 
and  in  the  Cohutta  Mountains  of  Murray  County  in  the  last,  are 
numerous  beds  of  very  clean  white  or  greenish  fibrous  talc  occurring 
in  part,  at  least,  in  connection  with  the  marble  beds.  Some  of  the 
material  is  soft,  white,  and  almost  translucent,  while  other  is  tough 
and  semi-translucent,  horn-like.  The  beds  are  mostly  very  irregular 
in  extent  as  well  as  in  quality  of  material. 

According  to  Dr.  Pratt  the  talc  formation  begins  in  Swain  County 
about  six  miles  east  of  the  Valley  River  Mountains,  following  up  the 
valley  of  the  Nantehala  to  near  the  Macon  County  line,  whence  it 
ascends  Nelson  Creek  ravine,  crossing  the  mountain  at  Red  Marble 
Gap.  Entering  Cherokee  County  it  then  follows  Valley  River,  cross- 
ing it  and  the  Hiawassee  near  Murphy  and  following  thence  the 
Nottely  River  Valley  into  Georgia.  The  country  rock  of  the  talc 
region  is  mainly  marble  and  quartzite,  bordered  by  gneiss  and 
crystalline  schists,  the  talc  itself  occurring  in  connection  with  the 
marble  and  lying  for  the  most  part  directly  between  the  marble 
and  quartzite,  but  sometimes  inclosed  wholly  in  the  marble.  The 
material  is  found  in  lenticular  masses  and  is  of  good  quality  only 
where  the  beds  have  been  protected  by  the  capping  of  quartzite; 
elsewhere  it  is  more  or  less  stained  by  iron  oxides,  and  otherwise 
injured.  There  is  a  considerable  variation  in  the  character  of 
the  talc  throughout  the  region.  To  the  east  of  Red  Marble  Gap 
it  is  of  a  bluish- white  color  and  much  of  it  sufficiently  compact  to 
allow  of  its  being  cut  and  used  for  slate  pencils;  that  to  the  west  is 
of  a  pale  greenish-white  to  bluish-white  color,  and  more  fibrous 
and  foliated.  All  the  varieties  are  regarded  by  Pratt  as  alteration 
products  of  tremolite. 

Soapstone  occurs  mainly  associated  with  the  older  crystalline 
rocks  and  in  some  cases  is  undoubtedly  an  altered- eruptive;  in  others 
there  is  a  possibility  of  its  being  a  product  of  metamorphism  of  mag- 
nesian  sedimentaries.  The  principal  beds  now  known  lie  in  the 
Appalachian  regions  of  the  eastern  United  States,  though  others  have 
recently  been  found  in  California,  and  there  is  no  reason  for  supposing 
that  many  more  may  not  exist  in  the  Rocky  Mountain  regions.  The 
beds,  if  such  they  can  be  called,  are  not  extensive,  as  a  rule,  but  occur 


212  THE  NON-METALLIC  MINERALS. 

in  lenticular  masses  of  uncertain  age  intercalated  with  other  mag- 
nesian  and  hornblendic  or  micaceous  rocks  frequently  more  or  less 
admixed  with  serpentine.  The  rock,  like  serpentine,  is  traversed 
by  bad  seams  and  joints,  and  the  opening  of  any  new  deposit  is 
always  attended  with  more  or  less  risk,  as  there  is  no  guarantee 
that  sound  blocks  of  sufficient  size  to  be  of  value  will  ever  be  ob- 
tainable. 

Localities. — An  extensive  bed  of  fine  quality  soapstone  was  dis- 
covered as  early  as  1794  at  Francestown,  New  Hampshire.  This 
was  worked  as  early  as  1802,  and  up  to  1867  some  5,500  tons  had 
been  quarried  and  sold.  Other  beds,  constituting  a  part  of  the  same 
formation,  occur  in  Weare,  Warner,  Canterbury,  and  Richmond, 
in  the  same  State.  All  of  these  have  been  operated  to  a  greater 
or  less  extent. 

Fine  beds  of  the  stone  also  occur  in  the  town  of  Orford,  and 
an  important  quarry  was  opened  as  early  as  1855  in  Haverhill,  but 
it  has  not  been  worked  continuously. 

At  least  sixty  beds  of  soapstone  are  stated  x  to  occur  in  Vermont, 
mostly  located  along  the  east  side  of  the  Green  Mountain  range, 
and  extending  nearly  the  entire  length  of  the  State.  The  rock 
occurs  associated  with  serpentine  and  hornblende,  and  the  beds, 
as  a  rule,  are  not  continuous  for  any  distance,  but  have  a  great  thick- 
ness in  comparison  with  their  length.  Several  isolated  outcrops  may 
occur  on  the  same  line  of  strata,  perhaps  miles  apart,  in  many  cases 
alternating  with  beds  of  dolomitic  limestone. 

Beds  occur  in  the  towns  of  Readsboro,  Marlboro,  New  Fane, 
Windham,  Townsend,  Athens,  Grafton,  Andover,  Chester,  Caven- 
dish, Baltimore,  Ludlow,  Plymouth,  Bridgewater,  Thetford,  Bethel, 
Rochester,  Warren,  Braintree,  Waitsfield,  Moretown,  Duxbury, 
Waterbury,  Bolton,  Stow,  Cambridge,  Waterville,  Berkshire,  Eden, 
Lowell,  Belvidere,  Johnson,  Enosburg,  Westfield,  Richford,  Troy, 
and  Jay.  Of  these  those  of  Grafton  and  Athens  are  stated  to  have 
been  longest  worked  and  to  have  produced  the  most  stone.  The 
beds  lie  in  gneiss.  Another  important  bed  occurs  in  the  town  of 
Weatherfield.  This,  like  that  of  Grafton,  is  situated  in  gneiss,  and 
the  material  can  be  had  in  inexhaustible  quantities.  It  was  first  worked 

1  Geology  of  Vermont,  1861,  Vols.  I  and  II. 


SILICA  TES.  2 13 

about  1847.  The  Rochester  beds  were  at  one  time  of  great  importance, 
the  stone  being  peculiarly  fine  grained  and  compact.  It  was  once 
much  used  in  the  manufacture  of  refrigerators.  The  bed  at  New 
Fane  occurs  in  connection  with  serpentine,  and  is  some  half  mile  in 
length  by  not  less  than  12  rods  in  width  at  its  northern  extremity. 

In  Massachusetts  quarries  of  soapstone  have  been  worked  from 
time  to  time  in  Lynnfield  and  North  Dana.  The  Lynnfield  stone 
occurs  associated  with  serpentine.  It  has  not  been  quarried  of  late, 
but  was  formerly  used  for  stove  backs,  sills,  and  steps.  In  New 
York  State  soapstone  and  talc  occur  in  abundance  near  Fowler  and 
Edwards  in  St.  Lawrence  County.  Some  of  this  is  very  pure, 
nearly  snow-white  talc,  and  is  quarried  and  pulverized  for  com- 
mercial purposes,  as  already  noted. 

In  Pennsylvania,  in  the  southern  edge  of  Montgomery  County, 
extending  from  the  northern  brow  of  Chestnut  Hill  between  the 
two  turnpikes  acrosss  the  Wissahickon  Creek  and  the  Schuylkill  to 
a  point  about  a  mile  west  of  Marion  Square,  there  occurs  a  long, 
straight  outcrop  of  steatite  and  serpentine.  The  eastern  and  central 
part  of  this  belt  on  the  southern  side  consists  chiefly  of  steatite,  while 
the  northern  side  contains  much  serpentine,  interspersed  through 
it  in  lumps.  Only  in  a  few  neighborhoods,  as  at  LaFayette,  does 
either  the  steatitie  or  serpentine  occur  in  a  state  of  sufficient  purity 
to  be  profitably  quaried.  (Plate  XIX.)  On  the  east  bank  of  the 
Schuylkill,  about  2  miles  below  Spring  Mill,  a  good  quality  of  mate- 
rial occurs  that  has  long  been  successfully  worked.  The  material 
is  now  used  principally  for  stoves,  fireplaces,  and  furnaces,  though 
toward  the  end  of  the  eighteenth  century  and  during  the  early  part 
of  the  nineteenth,  before  the  introduction  of  the  Montgomery  County 
marble,  it  was  in  considerable  demand  for  doorsteps  and  sills.  It 
proved  poorly  adapted  for  this  purpose,  owing  to  the  unequal  hard- 
ness of  the  different  constituents,  the  soapstone  wearing  away 
rapidly,  while  the  serpentine  was  left  projecting  like  knots,  or  "hob- 
nails in  a  plank." 

Several  small  deposits  of  soapstone  occur  in  Maryland,  and 
some  of  them  have  been  worked  on  a  small  scale.  The  material  is 
of  good  quality,  but  apparently  to  be  had  only  in  small  pieces. 

In  Virginia  soapstone  occurs  in  Fairfax,  Fluvanna,  and  Bucking- 


214  THE  NON-METALLIC  MINERALS. 

ham  counties.  There  is  also  a  bed  at  Alberene,  Albemarle  County, 
a  little  west  of  Green  Mountain.  This  is  the  bed  so  extensively 
worked  by  the  Alberene  Soapstone  Company.  From  these  points 
the  beds  extend  in  a  southwesterly  direction  through  Nelson  County, 
where  they  are  associated  with  serpentine;  thence  across  the  James 
River  above  Lynchburg,  and  present  an  outcrop  about  2  miles  west 
of  the  town  on  the  road  leading  to  Liberty;  also  one  some  2^  miles 
west  of  New  London.  Continuing  in  the  same  direction  the  bed 
is  seen  at  the  meadows  of  Goose  Creek,  where  it  has  been  quarried 
to  some  extent.  Parallel  ranges  or  soapstone  appear  near  the 
Pigg  River  in  Franklin  County.  About  30  miles  southwest  from 
Richmond,  at  Chula,  in  Amelia  County,  there  are  outcrops 
of  soapstone  said  to  be  of  fine  quality,  and  in  former  times  quite 
extensively  operated  by  the  Indians.  They  have  been  reopened 
within  a  few  years  and  the  material  is  now  on  the  market. 

North  Carolina  contains,  in  addition  to  an  abundance  of  the  finest 
grades  of  talc  and  steatite  as  already  noted,  beds  of  the  compact 
common  soapstone.  Deposits  in  Cherokee  and  Moore  counties 
furnish  especially  desirable  material  for  lubricating  and  other  pur- 
poses. Murphy,  Guilford,  Ashe,  and  Alamance  counties  are  also 
capable  of  affording  good  materials,  but  much  of  it  is  inaccessible 
at  present  on  account  of  poor  railroad  facilities. 

Beds  of  soapstone  are  stated  to  occur  in  Saline  County,  Arkansas, 
and  in  Chester,  Spartanburg,  Union,  Pickens,  Oconee,  Anderson, 
Abbeville,  Kershaw,  Fairfield,  and  Richmond  counties  in  South  Caro- 
lina. Llano  County,  Texas,  and  Santa  Catalina  Island,  California, 
also  contain  good  material  of  this  nature. 

Uses. — The  uses  to  which  talc  and  soapstone  are  put  vary 
greatly  according  to  purity  and  physical  characteristics.  The  white, 
fibrous  talc,  from  St.  Lawrence  County,  New  York,  is  used  as  a 
filler  in  paper  manufacture,  something  like  30  per  cent  of  the  weight 
of  printing  paper  being  made  up  of  this  material.  Pulverized  talc 
is  also  used  as  a  lubricator,  for  which  purpose  it  is  remarkably 
well  adapted.  Rubbed  between  the  thumb  and  finger  the  powder 
is  smooth  and  oily,  without  a  particle  of  grit.  It  is  also  used  in 
soap  making,  for  which  purpose  it  can,  however,  be  considered 
only  as  an  adulterant,  increasing  the  weight  but  not  the  cleaning 


?lS 

$  »• 

c   ~ 


SILICATES.  215 

properties  of  the  article.  It  is  further  used  as  a  dressing  for  fine 
leathers,  and  in  considerable  quantities  in  foundry  work.  Small 
quantities  are  used  by  shoe  and  glove  dealers,  and  large  quantities 
in  the  form  of  " talcum  powder"  for  toilet  purposes.  The  pure 
creamy-white  talc,  such  as  is  obtained  from  North  Carolina,  is 
used  for  crayons  and  slate  pencils,  while  the  still  finer,  crypto-crystal- 
line  varieties  are  used  by  tailors  under  the  name  of  French  chalk 
and  for  making  the  tips  for  gas  burners.  Fine  compact  grades  of 
a  somewhat  similar  rock  (agalmatolite)  are  used  extensively  in 
China  and  Japan  for  small  ornaments.  The  stone  is  readily  carved 
in  fine  sharp  lines,  and  is  a  general  favorite  for  making  the  grotesque 
images  for  which  these  countries  are  noted,  and  which  are  often  sold 
throughout  the  country  under  the  name  of  jadestone. 

The  following  account  of  the  soapstone  industry  of  China  is  taken 
from  the  Engineering  and  Mining  Journal  of  September  30,  1893. 
The  material  referred  to  as  soapstone  is,  however,  very  probably 
agalmatolite. 

"The  mines  are  distant  42  miles  from  Wenchow,  and  are  reached 
by  a  boat  journey  of  35  miles  up  the  river,  followed  by  a  land  journey 
of  7  miles  over  rough  ground.  The  hills  containing  steatite  are 
owned  by  20  to  30  families,  who  in  some  cases  work  the  mines  them- 
selves, in  others  engage  miners  to  do  it  on  their  account.  The 
galleries  are  driven  into  the  sides  of  the  hills,  and  are  often  nearly 
a  mile  in  length.  The  stone  when  first  extracted  is  soft,  hardening 
on  exposure  to  the  air.  It  is  brought  out  of  the  mine  in  shovels, 
and  is  sold  at  the  pit  mouth  to  the  carvers  at  a  uniform  price  of  about 
one-half  a  penny  per  pound.  This  when  the  purchaser  buys  it  in 
gross.  When  picked  over  the  mineral  varies  very  considerably  in 
value— according  to  the  color,  size  of  the  lump,  or  its  shape.  The 
colors  are  given  as  purple,  red,  mottled  red,  black,  dark  blue,  light 
blue,  gray,  white,  eggshell-white,  'jade,'  beeswax,  and  'frozen.* 
Of  these  'jade'  (the  white  variety,  not  the  green)  and  'frozen'  are 
the  most  valuable.  The  industry  finds  employment  for  some  2,000 
miners  and  carvers.  A  great  impetus  was  given  to  it  by  the  opening 
of  Wenchow  to  foreign  trade.  Previous  to  that  event  the  chief 
purchasers  were  officials  and  literary  men,  and  the  article  most  often 
carved  was  a  stamp  or  seal.  When  it  was  discovered  that  foreigners 


216  THE  NON-METALLIC  MINERALS. 

admired  the  stone,  articles  were  produced  to  meet  what  was  supposed 
to  be  their  taste.  Such  were  landscapes  in  low  or  high  relief,  flower 
vases,  plates,  card  trays,  fruit  dishes,  cups,  teapots,  and  pagodas. 
If  left  to  his  own  devices  the  native  carver  proceeds  first  to  examine 
his  stone,  much  as  a  cameo  cutter  would  do,  to  discover  how  best 
he  can  take  advantage  of  its  shape  and  shades  of  color."  (See 
further  under  Agalmatolite.) 

The  soapstones  are  suited  for  a  considerable  range  of  appli- 
cation. Although  so  soft,  they  are  among  the  most  indestructible 
and  lasting  of  rocks,  but  are  too  slippery  and  perhaps  of  too  somber 
a  color  for  general  structural  purposes.  At  present  the  chief  use  of 
the  material  in  the  United  States  is  in  the  form  of  thin  slabs  for  sinks, 
stationary  washtubs,  laboratory  fittings,  and  electric  switchboards. 
At  one  time  it  was  quite  extensively  used  throughout  New  England 
in  the  manufacture  of  stoves  for  heating  purposes  and  to  some  extent 
for  fire-brick,  the  well-seasoned  stone  being  thoroughly  fireproof. 
The  putting  upon  the  market  of  unseasoned  materials  or  of  material 
with  bad  veins,  which  caused  the  stone  to  crack  or  perhaps  fly  to 
fragments  when  subjected  to  high  temperature,  aroused  a  prejudice 
against  the  employment  of  this  material,  and  the  manufacture  is 
stated  to  have  been  to  a  considerable  extent  discontinued  as  a  con- 
sequence. In  the  manufacture  of  either  stoves  or  washtubs,  slabs 
of  considerable  size,  free  from  segregation  nodules  of  quartz,  pyrite, 
or  other  minerals,  or  from  dry  seams,  are  essential.  As  but  few  of 
the  now  known  outcrops  can  furnish  material  of  this  nature,  the  main 
part  of  the  business  of  the  country  is  in  the  hands  of  but  two  or 
three  companies.  The  waste  material  from  the  quarries,  or  the 
entire  output  in  certain  cases,  is  pulverized  and  used  as  a  lubricant 
or  white  earth,  as  is  the  micaceous  variety. 


13.  PYROPHYLLITE;  AGALMATOLITE;  AND  FINITE   (IN  PART). 

This    is    a   hydrous    silicate    of  aluminum    corresponding  to 

the    formula    H2O,    A12O3,    4SiO2.  The    analyses   given   below 

show    the    average    composition    of  the    material    as    it    occurs 
in    nature : 


SILICATES. 


217 


Locality. 

Silica. 

Alumina. 

Water. 

Remarks. 

Westana,  Sweden  .  . 

6<:  61 

26.00 

7  08 

S^^ith  small  amounts 

China 

66.38 

2?.Qs 

520 

of  iron,  magnesia 

Deep  River,  North  Carolina.. 

65-93 

29-54 

5-40 

and  lime. 

The  mineral  is  not  known  in  distinct  crystals,  but  occurs  rather 
in  foliated  lamellar,  massive  and  compact  forms,  closely  resembling 
some  forms  of  talc,  for  which  its  soapy  or  greasy  feeling  renders  it 
very  likely  to  be  mistaken,  though  its  hardness  (2  to  2.5)  is  somewhat 
greater.  The  prevailing  colors  are  white  or  greenish  gray  and  dull 
red,  variously  mottled. 

Occurrence. — The  principal  localities  furnishing  pyrophyllite  in 
any  considerable  quantities  in  the  United  States  are  in  the  extreme 
north-central  portion  of  Moore  County  and  the  south-central  por- 
tion of  Chatham  County,  North  Carolina.  The  deposits  are  asso- 
ciated with  slates,  but  usually  separated  from  them  by  bands  of 
siliceous  and  iron  breccia  from  100  to  150  feet  in  thickness.  The 
formation  has  a  strike  of  approximately  55°-6o°  E.  and  dips  6o°- 
7o°+NW.,  and  has  been  traced  for  a  distance  of  upward  of  6  miles. 
Some  of  the  bands  are  highly  siliceous  and  of  poor  quality.  Others 
are  entirely  free  from  grit.  Small  seams  of  quartz  often  penetrate 
the  bed,  and  occasional  particles  of  chlorite  and  hematite  occur, 
giving  the  material  a  speckled  appearance.  Of  the  500  feet  max- 
imum thickness  of  the  bed  not  over  100  feet  are  workable,  and  of 
this  not  more  than  25  per  cent  can  be  expected  to  prove  merchant- 
able.1 

Uses. — The  more  compact  varieties,  like  that  of  Deep  River, 
are  used  for  making  slate  pencils  and  tailors'  chalk,  or  French 
chalk,  so-called.  The  still  more  compact  forms,  known  as  agal- 
matolite  and  pagodite,  are  used  extensively  by  the  Chinese  and 
Japanese  for  making  small  images  and  art  objects  of  various  kinds. 
Dana  states,  however,  that  a  part  of  the  so-called  Chinese  agal- 
matolite  is  in  reality  pinite  and  a  part  steatite.  The  objects  sold 
by  Chinese  dealers  at  the  various  expositions  of  late  years  under 
the  name  of  jadestone  are,  however,  of  agalmatolite. 


1  J.  H.  Pratt,  Economic  Paper  No.  3,  North  Carolina  Geological  Survey,  1900. 


2l8 


THE  NON-METALLIC  MINERALS. 


Finite:  Agalmatolite  in  part.  Composition,  a  hydrous  silicate 
of  aluminum  and  the  alkalies.  According  to  Dana,1  the  name  is 
made  to  include  a  large  number,  of  alteration  products  of  white 
spodumene,  nepheline,  feldspar,  etc.  Professor  Heddle  has  de- 
scribed 2  a  pinite  (agalmatolite)  occurring  in  large  lumps  of  a  sea- 
green  color,  surrounding  crystalline  masses  of  feldspar  in  the  granites 
of  Scotland,  and  which  he  regards  as  alteration  products  of  oligo- 
clase.  The  composition  as  given  is:  Silica,  48.72  per  cent;  alumina, 
31.56  per  cent;  ferric  oxide,  2.43  per  cent;  magnesia,  1.81  per 
cent;  potash,  9.48  per  cent;  soda,  0.31  per  cent;  water,  5.75  per 
cent. 

14.  SEPIOLITE;   MEERSCHAUM. 

This  mineral  is  a  hydrous  silicate  of  magnesia,  having  the  com- 
position indicated  by  the  formula  H4Mg2Si3O10,=  silica,  60.8  per 
cent;  magnesia,  27.1  per  cent;  water,  12.1  per  cent.  The  prevail- 
ing colors  are  white  or  grayish,  sometimes  with  a  faint  yellowish, 
reddish,  or  bluish-green  tinge.  It  is  sufficiently  soft  to  be  impressed 
by  the  nail,  opaque,  with  a  compact  structure,  smooth  feel,  and 
somewhat  clay-like  aspect;  rarely  it  shows  a  fibrous  structure.  In 
nature  it  rarely  occurs  in  a  state  of  absolute  purity.  The  first  three 
of  the  following  analyses  are  quoted  from  Dana's  Mineralogy: 


Locality. 

SiO2. 

MgO. 

PeO. 

H2O. 

CO-2. 

Turkey 

61   17 

28    43 

o  06 

o  8^ 

o  67 

Greece 

61   30 

28    30 

o  08 

974 

o  ^6 

Utah  (fibrous) 

C2  07 

22  so 

/CuO 

r    O     OO 

/  Hygroscopic  H2O 

New  Mexico  

^7.10 

27  16 

1  0.87 
Trace 

14.    78 

\                         8.80 

The  name  is  from  the  German  words  Meer,  sea,  and  Schaum, 
foam,  in  allusion  to  its  appearance.  The  chief  commercial  localities 
are  in  Asia  Minor,  Bosnia,  and  New  Mexico. 


1  System  of  Mineralogy,  6th  ed.,  p.  621. 

2  Mineralogical  Magazine,  IV,  p.  215. 


SILICATES.  219 

Mode  of  occurrence  and  origin. — According  to  J.  Lawrence 
Smith,1  the  Asiatic  material  occurs  in  the  form  of  nodular  masses 
in  alluvial  deposits  on  the  plain  of  Eski-Shehr.  It  was  thought  by 
him  to  owe  its  origin  to  the  carbonate  of  magnesia  derived  from  the 
adjacent  mountains,  decomposed  after  its  separation  by  waters 
containing  silica.  This  supposition  he  based  in  part  upon  the 
presence  of  the  carbonate  in  variable  amounts  in  the  sepiolite  nodules, 
and  in  part  upon  their  association,  even  in  the  same  mass,  with 
serpentine.  In  the  light  of  to-day  it  would  seem  more  probable  that 
the  serpentine  was  itself  a  product  of  alteration  of  an  igneous  mag- 
nesian  rock  (peridotite)  and  the  sepiolite  and  magnesite  (MgCOs) 
incidental  products,  or  perhaps  products  of  a  further  alteration  of  the 
serpentine  in  its  turn.  F.  Katzer  describes2  the  Bosnian  material 
as  likewise  occurring  in  form  of  lumps  and  masses  irregularly  dis- 
tributed throughout  a  Tertiary  conglomerate,  and  also  in  lumps, 
veins  and  aggregates  in  serpentine,  the  last  named  rock  being  de- 
rived from  a  bronzite  peridotite.  He  conceives  the  alteration  (ser- 
pentinization)  to  have  been  brought  about  through  the  agency  of 
water-carrying  carbonic  acid,  a  part  of  the  magnesia  separating  out 
as  a  carbonate,  while  a  smaller  portion  combined  with  silica  and 
water  to  form  the  sepiolite. 

In  an  article  in  the  Cyclopedia  of  Arts  and  Sciences  it  is  stated 
that  the  meerschaum  of  the  Crimea  forms  a  stratum  some  2  feet 
thick  beneath  a  much  thicker  stratum  of  marl.  Cleveland  in  his 
elementary  treatise  on  minerals  (1822)  states  that  at  Anatolia,  in 
Asia  Minor,  meerschaum  occurs  in  the  form  of  a  vein  more  than 
6  feet  wide  (?),  in  compact  limestone.  At  Vallecas,  Spain,  a  very 
impure  form  is  stated  to  occur  in  the  form  of  beds  and  in  such 
abundance  as  to  be  utilized  for  building  material.  Aside  from  the 
localities  above  mentioned,  sepiolite. is  known  to  occur  in  Greece, 
at  Hrubschitz  in  Moravia,  and  in  Morocco,  in  all  cases  being  asso- 
ciated with  serpentine,  with  which  it  is  apparently  genetically 
related. 


1  American  Journal  of  Science,  1849,  VIII,  p.  285. 

2  Berg-  u.  Huttenmann.  Jahrb.,  LVII,  p.  65,  Abstr.  in  Chem.  Abstr.,  Ill,  October 

10,  1909,  p.  2287. 


220  THE  NON-METALLIC  MINERALS. 

According  to  Kunz,1  meerschaum  has  occasionally  been  met  with 
in  compact  masses  of  smooth,  earthy  texture  in  the  serpentine 
quarries  of  West  Nottingham  Township,  Chester  County,  Pennsyl- 
vania. Only  a  few  pieces  were  found,  but  they  were  of  good  quality. 
It  also  occurs  in  grayish  and  yellowish  masses  in  the  serpentine  in 
Concord,  Delaware  County,  Pennsylvania.  Masses  of  pure  white 
material,  weighing  a  pound  each,  have  been  found  in  Middletown, 
in  the  same  county,  and  of  equally  good  quality  at  the  Cheever 
Iron  Mine,  Richmond,  Massachusetts,  in  pieces  over  an  inch  across, 
also  in  serpentine  at  New  Rochelle,  Westchester  County,  New 
York.  Two  localities  for  meerschaum  have  of  late  years  been 
exploited  in  the  upper  Gila  valley  of  New  Mexico,  one  some  23 
miles  northeast  of  Silver  City,  on  Alunogen  Creek  and  the 
other  about  12  miles  northwest  of  the  same  city,  in  the  canon 
of  Bear  Creek.  The  rock  forming  the  walls  of  this  canon,  and  in 
which  the  meerschaum  occurs,  is  a  gray  cherty  limestone  of  sup- 
posed Ordovician  Age,  with  intercalated  strata  of  sandstone.  The 
meerschaum  is  reported2  as  occurring  in  veins,  lenses,  seams,  and 
balls,  all  but  the  last  named  filling  fractures  and  joints  in  the  lime- 
stone. Chert  is  a  common  gangue  mineral,  and  with  it  occur  quartz, 
calcite  and  clay.  Two  types  or  varieties  of  material  are  found: 
One  in  the  form  of  irregular  nodules  of  all  sizes  up  to  several  inches 
in  diameter,  having  an  uneven  fracture,  and  somewhat  fibrous, 
leathery,  porous  structure,  and  the  other  in  a  more  massive  form 
and  compact  nature.  The  origin  of  the  material  seems  to  not  have 
been  worked  out,  nor  has  the  commercial  value  of  the  deposit  yet 
been  fully  demonstrated.  The  analysis  given  on  p.  218  is  of  a 
sample  from  the  Dorsey  claim  on  Bear  Creek. 

Uses. — The  mineral  owes  its  chief  value  to  its  adaptability  for 
smokers'  use,  being  utilized  in  the  manufacture  of  what  are  known 
as  meerschaum  pipes.  In  Algeria  a  soft  variety  is  used  in  place 
of  soap  at  the  Moorish  baths  and  for  washing  linen. 

According  to  a  writer  in  the  Engineering  and  Mining  Journal,3 
the  Eski-Shehr  mineral  is  mined  from  pits  and  horizontal  galleries  in 

1  Gems  and  Precious  Stones,  p.  189. 

2  D.  B.  Sterrett,  Bulletin  No.  340,  U.  S.  Geological  Survey. 

3  Volume  LIX,  1895,  p.  464. 


SILICATES.  221 

much  the  same  manner  as  coal.  As  first  brought  to  the  surface 
it  is  white,  with  a  yellowish  tint,  and  is  covered  with  red  clayey 
soil.  In  this  condition  it  is  sold  to  dealers  on  the  spot.  Before 
exporting  the  material  is  cleaned,  dried,  and  assorted,  the  drying 
taking  place  in  the  open  air,  without  artificial  heat  in  summer,  and 
requiring  from  five  to  six  days.  The  bulk  of  the  material  is  sent 
direct  to  Vienna  and  Paris. 

15.  CLAYS. 

The  term  clay  as  commonly  used  is  made  to  comprise  materials  of 
widely  diverse  origin  and  mineral  and  chemical  composition,  but 
which  have  in  common  the  property  of  plasticity  when  wet,  and 
that  of  becoming  indurated  when  dried  either  by  natural  or  artificial 
means.  Of  so  variable  a  nature  is  the  material  thus  classed  that 
no  brief  definition  can  be  given  that  is  at  all  satisfactory.  One 
may  perhaps  describe  the  clays,  as  a  whole,  as  heterogeneous  ag- 
gregates of  hydrous  and  anhydrous  aluminous  silicates,  free  silica, 
and  ever-varying  quantities  of  free  iron  oxides  and  calcium  and 
magnesian  carbonates,  all  in  a  finely  comminuted  condition. 

Origin  and  mode  of  occurrence. — The  clays  are  invariably  of 
secondary  origin — that  is,  they  result  from  the  decomposition  of 
pre-existing  rocks  and  minerals  and  the  accumulation  of  their  less 
soluble  residues,-  either  in  place  (residual  clays)  or  through  the 
transporting  power  of  ice  and  water  (drift  clays).  That  silicate 
of  aluminum  is  so  characteristic  a  constituent  of  nearly  all  clays 
is  due  to  the  fact  that  this  substance  is  one  of  the  most  insoluble 
of  natural  compounds,  and  hence  when,  under  the  action  of  atmos- 
pheric or  subterranean  agencies,  rocks  decompose  and  their  more 
soluble  constituents — as  lime,  magnesia,  potash,  soda,  or  even 
silica — are  removed,  the  aluminous  silicate  remains. 

The  kaolins,  which  may  be  regarded  as  the  simplest  of  clays, 
are  the  product,  mainly  at  least,  of  the  decomposition  of  feldspars, 
a  form  of  decomposition  which  consists  essentially  of  hydration 
and  a  more  or  less  complete  removal  of  the  lime  and  alkalies  and 
a  part  of  the  silica.  The  following  tables  show  the  composition 
of  the  common  feldspars  and  the  approximate  loss  and  gain  of 


222 


THE  NON-METALLIC  MINERALS. 


material  they  undergo  in  passing  into  the  condition  of  kaolin.  The 
formula  Si2O9Al2H4  given  is,  it  should  be  noted,  that  of  the  mineral 
kaolinite,  of  which  the  material  kaolin  is  commonly  regarded  as  an 
impure  form. 


SiO2 

A1203 

K,0 

H,0 

% 

i.     Orthoclase  

64.86 

18.29 

16.85 

IOO.OO 

Lost  .  ..  

43-24 

16.85 

60.09 

Taken  up  

6-45 

6-45 

Kaolinite  

21.62 

18.29 

6.45 

46.36 

2.     Albite  

Si02 
68.81 

A1203 

19.40 

Na20 
11.79 

H20 

% 

IOO.OO 

Lost  

45-87 

11.79 

57-66 

Taken  up  

6.85 

6.85 

Kaolinite  

22.94 

19.40 

6.85 

49.19 

Si02 

A1203 

CaO 

H20 

% 

3.     Anorthite  

43-30 

36.63 

20.07 

IOO.OO 

Lost  

20.07 

20.07 

Taken  up  

12.92 

12.92 

Kaolinite  

43-3° 

36-63 

12.92 

92.85 

From  this  it  appears  that,  in  the  case  of  orthoclase  and  albite, 
two-thirds  of  the  silica  and  all  the  alkalies  are  removed.  In  all, 
over  half  of  the  feldspathic  constituents  are  lost  during  the  transi- 
tion, while,  in  the  anorthite,  only  the  lime  is  carried  away.  The 
proportional  loss  and  gain  is  shown  as  follows: 

Orthoclase.  .     2Si3O8AlK  -  4SiO2  -  K2O  +  2H2O  =  Si2O9Al2H4. 
Albite  ......     2Si3O  8AlNa  -  4SiO2  -  Na2O  +  2H2O  =  Si2O9Al2H4. 

Anorthite.  .  .     Si2O8Al2Ca-  CaO  +  2Hp=  Si2O9Al2H4. 


In  other  words,  two  molecules  of  albite  or  orthoclase  are  neces- 
sary for  the  formation  of  one  molecule  of  kaolin,  while,  in  the  case  of 
anorthite,  one  molecule  is  sufficient  to  produce  one  molecule  of 
kaolin. 

As  to  the  method  by  which  this  decomposition  is  brought  about 
authorities  differ.  It  has  been  commonly  assumed  that  the  same 
was  a  purely  superficial  phenomenon,  a  form  of  weathering.  The 
observed  frequent  asociation  of  kaolin  with  fluorine  minerals  led 
von  Buch  and  Daubree  to  suggest  that  in  certain  instances  the 
kaolinization,  as  this  form  of  decomposition  is  called,  might  be 
due  to  exhalations  of  fluorhydric  acid.  J.  H.  Collins  showed  by 
experiment  the  possibility  of  such  an  origin,  and  was  led  to  think, 


SILICATES.  22$ 

in  the  case  of  veins  and  bands  sometimes  extending  far  below  the 
drainage  level,  no  other  conclusion  was  tenable.1  Dr.  Heinrich 
Ries,  in  a  paper  read  before  the  American  Ceramic  Society  in  1900, 
gave  it  as  his  opinion  that  the  kaolins  of  Cornwall  (England)  and 
possibly  those  of  Zettlitz  in  Bohemia  were  of  deep-seated  origin  and 
due  to  fluoric  exhalations,  as  noted  above.  Recently  H.  Rosier 
has  come  forward  with  an  apparently  exhaustive  paper  in  which  he 
advocates  this  origin  for  all  kaolins.2  Inasmuch,  however,  as  many 
American  kaolins  do  not  occur  in  veins,  but  so  far  as  observed  are 
merely  superficial  phases  of  granitic  decomposition,  so  far-reaching 
a  conclusion  cannot  at  present  be  accepted  unqualifiedly.  The 
fact  that  a  large  portion  of  American  kaolin  deposits  occur,  so  far 
as  known,  in  regions  south  of  the  glacial  limit  seems  to  substantiate 
the  prevailing  opinion  that  such  are  due  to  long-continued — secu- 
lar— decay  of  rock  masses  through  the  action  of  heat  and  cold,  mois- 
ture and  the  carbonic  acid  of  rainfalls,  in  short  are  due  to  weathering 
processes,  as  are  many  of  the  common  clays.  It  has  been  repeatedly 
shown  that  rocks  of  any  type  containing  aluminous  silicates  will  on 
prolonged  decomposition  through  atmospheric  influences  break  down 
into  clayey  soils  and  clays,  the  nature  of  which  is  dependent  to  a 
considerable  extent  upon  the  character  of  the  parent  rock.  Such 
are  the  residual  clays  of  non-glaciated  regions,  and  of  limestone 
caves,  and  perhaps  also  the  so-called  Indianaite  of  Lawrence  County, 
Indiana.3 

The  assorting  and  transporting  power  of  running  waters  rarely 
allows  beds  of  kaolin  or  other  residual  clays  to  remain  in  a 
condition  of  virgin  purity  or  even  in  the  place  of  their  origin.  The 
minute  size  and  the  shape  of  the  constituent  particles  are  such  as 
to  render  them  easy  of  transportation  by  rains  and  running  streams 
to  be  redeppsited  in  regularly  stratified  and  laminated  beds  when 
the  streams  lose  their  carrying  power  by  flowing  into  lakes  and 
seas.  It  is  through  such  agencies  that  have  been  formed  the  bedded 
Leda  and  Champlain  clays  of  the  glacial  period,  the  Cretaceous 

1  Mineralogical  Magazine,  VII,  1886-87,  p.  217. 

2  Neues  Jahrb.  fur  Min.  Geol.  u.  Pal.     XV  Beilage-Band,  2.  Heft,  1902. 

3  See  Rocks,  Rockweathering,  and  Soils,  2d  ed.,  pp.  150-273. 


224  THE   NON-METALLIC  MINERALS. 

clays  of  New  Jersey  and  the  fire  clays  of  the  Coal  Measures,  though 
their  original  constituents  may  have  been  of  purely  chemical  or 
of  mechanical  origin. 

The  glacial  clays  of  Wisconsin  have  been  described  by  Cham- 
berlain as  owing  their  origin  mainly  to  the  mechanical  grinding 
of  glacial  ice  upon  strata  of  limestone,  sandstone,  and  shale,  resulting 
in  a  comminuted  product  that  now  contains  from  25  to  50  per  cent 
of  carbonates  of  lime  and  magnesia.  This  product  of  glacial  grind- 
ing was  separated  from  the  mixed  stony  clays  produced  by  the  same 
action  by  water  either  immediately  upon  its  formation  or  in  the 
lacustrine  epoch  closely  following.  The  process  of  separation 
must  have  been  rapid  and  comparatively  free  from  the  agency  of 
carbonated  waters,  otherwise  the  lime  and  magnesia  would  have 
been  leached  out. 

The  formation  of  beds  of  clay  has  been  confined  to  no  par- 
ticular period  of  the  earth's  history,  but  has  evidently  gone  on  ever 
since  the  first  rocks  were  formed  and  when  rock  decomposition  began. 
The  older  beds  are  as  a  rule  greatly  indurated  and  otherwise  altered, 
and  in  many  instances  no  longer  recognizable  as  clays  at  all. 
Throughout  the  Appalachian  region  clay  beds  of  Cambrian  and 
Silurian  ages  have,  by  the  squeezing  and  shearing  incident  to  the 
elevation  of  this  mountain  system,  become  converted  into  argillites 
and  roofing  slates. 

Mineral  and  chemical  composition. — Formed  thus  in  a  variety 
of  ways,  and  consisting  frequently  of  materials  brought  from  diverse 
sources,  it  is  easy  to  comprehend  that  the  substances  ordinarily 
grouped  under  the  name  of  clay  may  vary  widely  in  both  mineral 
and  chemical  composition.  It  may  be  said  at  the  outset  that  the 
statement  so  frequently  made  to  the  effect  that  kaolinite  or  even 
kaolin  is  the  basis  of  all  clays  is  not  well  substantiated. 

Kaolinite  is  in  itself  not  properly  a  clay,  nor  is  it  plastic.  Further, 
in  many  cases  it  is  present  only  in  non-essential  quantities.  More 
open  to  criticism  yet,  because  more  concise,  is  the  statement  some- 
times made  that  clay  is  a  hydrated  silicate  of  alumina  having  the 
formula  Al2C)3,2SiO2-f  2H2O.  It  is  doubtful  if,  with  the  exception 
of  kaolin  and  halloysite,  a  clay  exists  which  could  be  reduced  to 
such  a  formula  excepting  by  a  liberal  exercise  of  the  imagination. 


SILICATES.  22$ 

There  is  scarcely  one  of  the  silicate  minerals  that  will  not  when 
sufficiently  finely  comminuted  yield  a  substance  possessing  those 
peculiar  physical  properties  of  unctuous  feel,  plasticity,  color,  and 
odor  which  are  the  only  constant  characteristics  of  the  multi- 
tudinous and  heterogeneous  compounds  known  as  clays.1  Dau- 
bree,  as  long  ago  as  1878,2  pointed  out  the  fact  that  by  the 
mechanical  trituration  of  feldspars  in  a  revolving  cylinder  with 
water,  an  impalpable  mud  was  obtained,  which  remained  many 
days  in  suspension,  and  on  drying  formed  masses  so  hard  as  to 
be  broken  only  with  a  hammer,  resembling  the  argillites  of  the 
Coal  Measures. 

The  kaolins,  when  examined  under  the  microscope,  are  found 
to  consist  largely  of  extremely  minute  colorless  shreds  of  material 
which  may  be  kaolinite;  intermixed  with  this  are  fragments  of 
undecomposed  feldspars  and  particles  of  quartz  and  other  refrac- 
tory minerals  as  tourmaline,  iron  ores,  mica,  etc.,  that  were  con- 
stituents of  the  parent  rock  and  have  escaped  decomposition.  The 
ordinary  residual  clays  have  a  yet  more  indefinite  composition,  as  a 
rule  are  more  or  less  ferruginous  and  contain  sand  particles,  grains 
of  magnetite,  titanic  iron,  garnet,  rutile  or  any  of  the  less  destructible 
minerals.  The  drift  or  transported  clays  are  like  heterogeneous 
aggregates.  Prof.  W.  O.  Crosby  has  shown  that  the  ordinary  glacial 
Champlain  or  Leda  clays  of  Cambridge,  Massachusetts,  contain 
but  from  one-fourth  to  one-third  their  bulk  of  what  he  designates 
"true  clay,"  the  remainder  being  finely  comminuted  material  of 
various  kinds  which  he  calls  rock  flour.  The  brick  clays  at  Lewis- 
ton  and  vicinity  contain,  as  shown  by  the  microscope,  a  compara- 
tively small  amount  of  material  that  can  be  designated  kaolin,  but 
carry  particles  of  free  quartz,  scales  of  mica,  bits  of  still  undecom- 
posed feldspar  and  other  silicate  minerals,  and  more  rarely  tourma- 
line, etc.  Many  of  these  clays  are  highly  calcareous,  also — indeed 

1  Referring  to  the  odor  of  clay  when  a  shower  of  rain  first  begins  to  wet  a  dry, 
clayey  soil,  Mr.  C.  Tomlinson  has  remarked  that  it  is  commonly  attributed  to  alumina, 
and  yet  pure  alumina  gives  off  no  odor  when  breathed  upon  or  wetted.  The  fact  is, 
the  peculiar  odor  referred  to  belongs  only  to  impure  clays,  and  chiefly  to  those  that 
contain  oxide  of  iron.  (Proceedings  of  the  Geological  Association,  I,  p.  242;  quoted 
in  Woodward's  Geology  of  England  and  Wales,  p.  439.) 

'Geologic  Expe"rimentale,  1879,  p.  251. 


226  THE  NON-METALLIC  MINERALS. 

both  lime  and  magnesia,  in  the  form  of  carbonate,  are  common  con- 
stituents of  any  but  the  residual  clays.  The  alkalies  potash  and 
soda  are  also  common  constituents,  though  occurring  as  silicates 
in  the  undecomposed  residual  material.  Iron  in  some  of  its  forms, 
as  hydrated  oxide,  carbonate  or  sulphide,  is  an  almost  universal 
constituent  of  clays  of  all  kinds. 

The  above  remarks  will  explain  why  a  purely  chemical  analysis 
of  a  clay  may  be  of  little  value  for  the  purpose  of  ascertaining  its 
suitability  for  any  particular  purpose.  It  is  essential  that  we  know 
not  merely  the  presence  or  absence  of  certain  elements,  but  also 
how  these  elements  are  combined.  Further  than  this,  except  in 
brick  and  tile  making,  few  clays  are  used  in  their  natural  condition, 
being  first  purified  by  washing  or  mixed  with  other  constituents  to 
give  them  body  or  fire-resisting  properties. 

Kinds  and  classification. — From  a  geological  standpoint  the 
clays  may  be  divided  into  two  general  classes,  as  above  noted,  (i) 
residual,  and  (2)  transported,  the  first  class  including  a  majority  of 
the  kaolin,  halloysite,  etc.,  and  the  second  the  ordinary  brick  and 
potters'  clays,  the  loess,  adobe,  Leda,  and  the  bedded  alluvial  deposits 
of  the  Cretaceous,  Carboniferous,  and  other  geological  periods. 
Special  names,  based  upon  such  properties  as  render  them  peculiarly 
adapted  to  economic  purposes,  are  common.  We  thus  have  (i) 
the  kaolin  and  China  clay,  (2)  potters'  clay,  (3)  pipe  clay,  (4)  fire 
clay,  (5)  brick  tile,  and  terra  cotta  clays,  etc.,  (6)  slip  clays,  (7) 
adobe,  and  (8)  fullers'  earth.  These  will  be  discussed  in  the  order 
given,  though  they  must  necessarily  be  discussed  but  briefly,  since 
the  subject  of  clays  alone  could  be  made  to  far  exceed  the  entire 
limits  of  the  present  volume.  The  names  fat  and  lean  clays  are 
workmen's  terms  for  clays  relatively  pure  and  plastic  or  carrying 
a  large  amount  of  mechanical  admixtures,  such  as  quartz  sand. 
The  term  ganister  is  sometimes  applied  to  a  siliceous  fire-clay  or  a 
mixture  of  fire-clay  and  sand  used  for  refractory  purposes  in  steel 
and  iron  works.1 

•J  The  name  is  somewhat  loosely  applied,  and  incapable  of  exact  definition.  Page, 
in  his  dictionary  of  terms,  defines  it  as  "The  local  name  for  a  fine  hard-grained  grit 
which  occurs  under  certain  coal  beds  in  Derbyshire,  Yorkshire,  and  the  north  of 
England." 


SILICATES.  227 

(i)  China  clays. — Under  the  name  of  kaolin,  or  China  clay,  it  is 
customary  to  include  a  white  pulverulent  highly  plastic  material, 
resulting  from  feldspathic  decomposition,  and  used  in  the  manu- 
facture of  the  finer  grades  of  porcelain  and  china  ware.  The  name 
kaolin,  as  applied,  is  due  to  a  misconception,  the  material  being 
supposed  to  be  similar  to  that  obtained  by  the  Chinese  at  Kaoling 
(Highridge),  and  from  which  was  made  the  high  grades  of  Chinese 
porcelain. 

According  to  Richthofen,1  however,  the  material  from  which 
the  porcelain  of  King-te-chin  is  made  is  not  kaolin  at  all,  as  the 
word  is  now  used,  but  a  hard  greenish  rock  which  occurs  intercalated 
between  beds  of  clay  slate.  He  says: 

"  This  rock  is  reduced,  by  stamping,  to  a  white  powder,  of  which 
the  finest  portion  is  ingeniously  and  repeatedly  separated.  This  is 
then  molded  into  small  bricks.  The  Chinese  distinguish  chiefly 
two  kinds  of  this  mineral.  Either  of  them  is  sold  in  King-te-chin 
in  the  shape  of  bricks,  and  as  either  is  a  white  earth,  they  offer  no 
visible  differences.  They  are  made  at  different  places,  in  the 
manner  described,  by  pounding  hard  rock,  but  the  aspect  of  the 
rock  is  nearly  alike  in  both  cases.  For  one  of  these  two  kinds  of 
material,  the  place  Kaoling  ('high  ridge')  was  in  ancient  times  in 
high  repute;  and  though  it  has  lost  its  prestige  since  centuries,  the 
Chinese  still  designate  by  the  name  'Kao-ling'  the  kind  of  earth 
which  was  formerly  derived  from  there,  but  is  now  prepared  in  other 
places.  The  application  of  the  name  by  Berzelius  to  porcelain 
earth  was  made  on  the  erroneous  supposition  that  the  white  earth 
which  he  received  from  a  member  of  one  of  the  embassies  occurred 
naturally  in  this  state.  The  second  kind  of  material  bears  the  name 
Pe-tun-tse  ('white  clay')." 

The  following  analysis  will  serve  to  show  the  average  compo- 
sition of  (i)  the  natural  material  from  King-te-Chin,  such  as  is 
used  in  the  manufacture  of  the  finest  porcelain;  (II)  that  from  the 
same  locality  used  in  the  so-called  blue  Canton  ware;  (III)  that  of 
the  English  Cornish  or  Cornwall  stone;  (IV)  washed  kaolin  from 

3  American  Journal  of  Science,  1871,  p.  180. 


228 


THE  NON-METALLIC  MINERALS. 


St.  Yrieux,  France,  and  (V)  washed  kaolin  from  Hockessin,  Dela- 


ware. 


Constituents. 

I. 

II. 

III. 

IV. 

V. 

Silica  

7-i.tt: 

7?.c<r 

73-  ">7 

48.68 

4.8  Tl 

Alumina. 

21  OO 

1898 

l6  4.7 

•?6  02 

77  02 

Ferric  oxide  .... 

.27 

7O 

Lime 

2.CC 

I  *8 

1.  17 

16 

Magnesia,  . 

•  I"? 

AO" 

1.  08 

.21 

r2 

ji 

Potash  

.46 

\               0 

(    41 

Soda 

2  OO 

}     5-84 

.58 

J  -4J- 

j        QA 

Combined  water  .  — 

2.62 

1.96 

245 

I3-I3 

12.83 

Total  .  . 

00.62 

OO  7O 

OQ  08 

OQ  8l 

IOO  OO 

Plate  XXI,  Figs,  i  and  2,  will  serve  to  show  the  shape  and 
kind  of  the  particles  in  the  mineral  kaolinite  and  in  a  prepared  sample 
of  the  Hockessin  kaolin,  as  seen  under  the  microscope. 

The  name  halloysite  is  given  to  a  white  or  yellowish  material 
closely  simulating  kaolin  in  composition,  but  occurring  in  indurated 
masses,  with  a  greasy  feel  and  luster,  and  which  adheres  strongly  to 
the  tongue,  a  property  due  to  its  capacity  for  absorbing  moisture.2 
As  it  is  utilized  for  much  the  same  purpose  as  is  kaolin,  it  is  included 
here. 

Halloysite  is  described  by  Gibson3  as  occurring  in  a  bed  some 
3  feet  in  thickness,  lying  near  the  base  of  the  Lower  Siliceous  (L. 
Carboniferous)  formation,  a  little  above  or  close  to  the  Black  Shale 
(Devonian),  in  Murphrees  Valley,  Alabama.  This  bed  has  been 
worked  with  satisfactory  results  near  Valley  Head,  in  Dekalb 
County.  The  present  writer  has  found  the  material  in  compara- 
tively small  quantities,  associated  with  kaolin,  in  narrow  veins  in 
the  decomposing  gneissic  rock  near  Stone  Mountain,  Georgia.  A 

1  Analyses  I  and  II  by  J.  E.  Whitfield,  Bulletin  27,  U.  S.  Geological  Survey;  III 
from  Langenbeck's  Chemistry  of  Pottery;  IV  from  Zirkel's  Lehrbuch  der  Pctro- 
graphie,  III,  p.  758,  and  V  by  George  Steiger,  U.  S.  Geological  Survey. 

3  This  property  is  characteristic  of  nearly  all  clay  compounds  when  they  are  dry. 
It  is  to  this  same  property  that  many  of  the  so-called  "madstones"owe  their  imagi- 
nary virtues.  Nearly  all  the  stones  of  this  type  examined  by  the  writer  have  proved 
to  be  of  indurated  clay,  halloysite,  or  a  closely  related  compound.  When  applied 
to  a  fresh  wound,  such  adhere  until  they  become  saturated  with  moisture,  when  they 
fall  away.  Their  curative  powers  are  of  course  wholly  imaginary. 

8  Geological  Survey  of  Alabama.     Report  on  Murphrees  Valley,  1893,  p.  121. 


FIG.  2. 
PLATE  XXI. 

FIG.  i,  Kaolinite,  and  FIG.  2,  Washed  Kaolin  as  Seen  under  the  Microscope. 
[U.  S.  National  Museum.] 

[Facing  page  228.] 


SILICATES. 


229 


similar  occurrence  is  described  near  Elgin,  Scotland.  Near  TiifTer, 
Styria,  halloysite  is  described1  as  occurring  in  extensive  thick  and 
veinlike  agglomerations  in  porphyry.  It  is  quite  pure,  and  in  the 
form  of  irregular  nodules  of  various  sizes,  frequently  with  a  pellucid, 
steatite-like  central  nucleus,  passing  outwardly  into  a  pure  white 
substance,  greasy  to  the  touch,  in  which  are  occasionally  included 
minute  pellucid  granules.  Outside  it  passes  into  an  earthy,  friable 
substance.  The  following  analyses  show  the  varying  composition 
of  halloysite  from  (I)  Elgin,  Scotland,  (II)  Steinbruck,  Styria,  and 
(III)  Detroit  Mine,  Mono  Lake,  California: 


Constituents. 

I. 

II. 

III. 

Silica 

•7Q    5O 

AO  7 

4.2  QI 

\lumina 

^8    S2 

^w./ 
^8  JO 

38.4. 

Limp 

C7? 

O.6o 

•J    7 
0.6 

IVIaffnesia 

o  83 

I.^O 

I.e 

Ferric  oxide 

I  42 

*'3 

Trace. 

fy^anGranese.  . 

O.2< 

Water.  .                    .    . 

IQ.34 

18.00 

18.00 

99.20 

A  white  chalky  halloysite  from  the  pits  of  the  Frio  Kaolin  Mining 
Company  in  Edwards  County,  Texas,  has  the  composition  given 
below  as  shown  by  analyses  made  in  the  laboratory  of  the  depart- 
ment of  Geology  in  the  National  Museum: 


Constituents. 

Per  Cent. 

Silica 

4c    82 

Alumina 

•2Q   77 

Potash 

O    3O 

Ignition 

11  18 

99.27 

The  material  is  somewhat  variable,  corresponding  in  composition 
to  the  halloysite  described  by  Dana,  and  being,  in  part,  non-plastic, 
and  in  part  plastic  to  an  extraordinary  degree.  The  plastic  portions 
are  almost  as  gritless  as  starch  paste.  Its  appearance  under  the 
microscope  is  shown  in  Plate  XXII,  Fig.  i,  the  interspaces  of  the 

1  Mineralogical  Magazine,  II,  1878,  p.  264. 


230  THE  NON-METALLIC  MINERALS. 

visible  angular  particles  being  occupied  by  the  pasty,  almost  amor- 
phous material.  The  particles  themselves  act  very  faintly  on  polar- 
ized light,  and  it  is  not  possible  to  determine  their  mineralogical 
nature  by  optical  means  alone.  Much  of  the  material  is  evidently 
of  a  colloidal  nature. 

The  name  Indianaite  was  given  by  Cox  to  a  variety  of  halloy- 
site  found  in  Lawrence  County,  Indiana,  and  regarded  by  him  as 
resulting  from  the  decomposition  of  Archimedes  (Lower  Carbonif- 
erous) limestone.  It  is  represented  as  forming  a  stratum  from 
6  to  10  feet  thick,  underlying  a  massive  bed  of  Coal  Measure  con- 
glomerate 100  feet  thick  and  overlying  a  bed  of  limonite  2  to  5  feet 
thick.  The  material  like  kaolin  is  used  in  the  manufacture  of 
porcelain  ware.  The  composition  as  given  by  Dana  is  as  follows: 
Silica  39  per  cent,  alumina  36  per  cent,  water  23.50  per  cent,  lime 
and  magnesia  0.63  per  cent,  alkalies  0.54  per  cent,  total  99.67  per 
cent. 

(2)  The  potters'  and  (3)  pipe  clays  belong  mainly  to  what  are 
known  geologically  as  bedded  clays,  and  are  as  a  rule  very  siliceous 
compounds,  carrying  in  some  instances  as  much  as  50  per  cent  of 
free  quartz  and  6  to  10  per  cent  of  iron  oxides  and  other  impurities. 
They  are  highly  plastic  and  of  a  white  to  blue,  gray,  or  brown  color 
and  burn  gray,  brown,  or  red.  The  tables  on  page  248  will  show 
the  varying  composition  of  materials  thus  classed. 

(4)  The  fire  clays,  so  called  on  account  of  their  refractory  nature, 
differ  mainly  in  the  small  percentages  of  lime  and  the  alkalies 
they  carry,  and  to  the  absence  of  which  they  owe  their  refractory 
properties. 

The  bedded  clays  include  also  most  of  the  brick,  tile,  and  terra 
cotta  clays.  In  the  United  States  they  reach  their  maximum  de- 
velopment in  strata  of  Cretaceous  and  Carboniferous  ages.  To 
the  Cretaceous  age  belong  the  celebrated  plastic  clays  of  New  Jersey 
and  South  Carolina  and  a  very  large  proportion  of  the  brick,  tile, 
and  terra-cotta  clays  of  Delaware,1  Maryland,  and  Virginia.  The 
New  Jersey  beds  are  very  extensively  utilized  in  Middlesex  County 

1  This  of  course  does  not  include  the  kaolin  deposits  of  Hockessin,  Newcastle 
County,  and  similar  deposits. 


M 


FIG.  i. 


FIG.  2. 

PLATE    XXII. 

FIG.  i,  Halloysite,  and  FIG.  2,  Glacial  (Leda)  Clay,  as  Seen  under  the  Microscope, 
[U.  S.  National  Museum.] 

[Facing  page  230.] 


SILICATES.  231 

and  fully  described  in  the  State  Geological  Reports,1  from  which 
the  following  section  is  taken  : 

Feet. 

(1)  Dark -colored  clay  (with  beds  and  laminae  of  lignite) 50 

(2)  Sandy  clay,  with  sand  in  alternate  layers 40 

(3)  Stoneware  clay  bed 30 

(4)  Sand  and  sandy  clay  (with  lignite  near  the  bottom) 50 

(5)  South  Amboy  fire-clay  bed 20 

(6)  Sandy  clay  (generally  red  or  yellow) 3 

(7)  Sand  and  kaolin 10 

(8)  Feldspar  bed 5 

(9)  Micaceous  sand  bed «, 20 

(10)  Laminated  clay  and  sand 30 

(u)  Pipe  clay  (top  white) 10 

(12)  Sandy  clay  (including  leaf  bed) 5 

(13)  Woodbridge  fire-clay  bed 20 

(14)  Fire-sand  bed 15 

Raritan  clay  beds: 

(15)  Fireclay 15 

(16)  Sandy  clay 4 

(17)  Potters'  clay 20 

Total 347 

The  Aiken,  or  Savannah  River  region  of  South  Carolina  furnishes 
a  remarkable  illustration  of  transported  or  bedded  clays  free  from 
admixture  with  foreign  materials.  These  clays  are  nearly  pure 
kaolin,  the  materials  of  which  were  derived  from  decomposing 
granites  and  brought  by  easterly  flowing  rivers  of  Cretaceous  times 
to  be  deposited  in  the  quiet  marginal  waters  of  the  then  existing 
seas.  The  beds  as  now  uplifted  are  overlaid  by  sand  and  gravels 
of  the  Lafayette  and  other  subdivisions  of  the  Pliocene  period,  and 
are  themselves  interbedded  with  sands  and  gravels  bearing  witness 
to  the  varying  strength  of  the  currents  instrumental  in  their  trans- 
portation. The  material  is  reported  as  yielding  on  analysis:  SiO2 
45.02  per  cent;  A12O3  38.98  per  cent;  Fe2O3  0.77  percent;  FiO2 
0.85  per  cent;  CaO  0.03  per  cent;  MgO  0.07  per  cent;  Na2O  0.55 
per  cent;  K2O  0.26  per  cent;  Ignition  13.58  per  cent.2 

1  Report  on  Clay  Deposits  of  Woodbridge,  South  Amboy,  and  other  places  in  New 
Jersey,  1878. 

2  A  Preliminary  Report  on  Clays  of  South  Carolina,  by  Earle  Sloan,  1904. 


232  THE  NON-METALLIC  MINERALS. 

The  following  section  from  Bulletin  No.  3  of  the  Geological 
Survey  of  Missouri  will  serve  to  show  the  alternating  character  of 
the  Coal  Measure  clays  at  St.  Louis  and  their  varying  qualities  as 
indicated  by  the  uses  to  which  they  are  put: l 

"(i)  Loess,  20  feet. 

"(2)  Limestone  (Coal  Measure),  5  feet. 

"  (3)  Clay,  white  and  yellow,  used  for  sewer-pipe  manufacture, 
called  'bastard  fire  clay,'  3  to  4  feet. 

"(4)  Clay,  yellow  and  red,  sold  for  paint  manufacture  and  for 
coloring  plaster  and  mortar,  called  'ochre,'  3  feet. 

"(5)  Clay,  gray  to  white,  used  for  paint  manufacture  and  filling, 
i  foot  6  inches. 

"  (6)  Pipe  clay,  variegated,  reddish  brown  and  greenish,  called 
'keel,'  12  feet. 

"(7)  Sandstone. 

"  (8)  Slaty  shale. 

"(9)  Coal. 

"  (10)  Fire  clay,  becoming  sandy  toward  the  base." 

When  first  mined  these  Coal  Measure  clays  are  usually  very 
hard,  but  on  exposure  to  the  weather  slake  and  fall  into  powder. 
They  are  as  a  rule  much  less  fusible  than  are  the  glacial  clays,  and 
are  used  mainly  in  the  manufacture  of  fire  brick,  sewer  pipe,  terra- 
cotta stoneware,  as  crocks,  fruit  jars,  jugs,  etc.,  glass  and  gas  retorts, 
smelting  pots,  etc.  Some  of  these  articles  are  made  direct  from  the 
natural  clays,  while  others  are  from  a  mixture  of  several  clays  or  of  a 
clay  mixed  with  powdered  quartz  and  feldspar. 

(5)  For  ordinary  brick-making  purposes  a  great  variety  of  ma- 
terials are  employed ;  in  some  cases  residuary  deposits,  and  in  others 
alluvial  and  sedimentary.  Throughout  the  glacial  regions  of  the 
United  States  a  fine  unctuous  blue-gray  material,  laid  down  in  estu- 
aries during  the  Champlain  epoch,  the  so-called  Leda  clays,  are 
the  main  materials  used  for  this  purpose.  The  bowlder  clays  of 
the  glacial  regions  are  also  sometimes  used  when  sufficiently  homo- 
geneous. 

1  Bulletin  No.  3,  Geological  Survey  of  Missouri,  1890. 


3 

P 


a 


SILICATES 


233 


The  prevailing  colors  of  the  Leda  clays  are  blue-gray  below 
the  zone  of  oxidation  and  yellowish  or  brownish  above.  They  all 
carry  varying  amounts  of  iron,  lime,  magnesia,  and  the  alkalies, 
and  when  burned  turn  to  red  of  varying  tints.  They  fuse  with 
comparative  ease  and  are  used,  aside  from  brick  and  tile  making, 
for  the  coarser  forms  of  earthenware,  as  flower  pots,  being  as  a 
rule  mixed  with  siliceous  sand  to  counteract  shrinkage.  The  mining 
of  such  material  is  of  the  simplest  kind,  and  consists  merely  of 
scraping  away  the  overlying  soil  and  sand,  if  such  there  be,  and 
removing  the  clay  in  the  form  of  sidehill  cuts  or  open  pits. 

Plate  XXIII,  facing  page  232,  shows  a  cut  in  one  of  the  beds  at 
Lewiston,  Maine.  The  material  here  is  fine  and  homogeneous, 
of  a  blue-gray  color,  and  contains  no  appreciable  grit.  It  is 
mixed  with  siliceous  sand  and  used  for  making  bricks,  baking 
red.  An  analysis  of  the  material  in  its  air-dry  state  yielded 
results  as  below: 


Constituents. 

Percentages. 

Silica  (SiO2) 

c6    1  7 

Alumina  (Al2Os) 

24.    2C 

Ferrous  oxide  (FeO) 

3^4. 

Lime  (CaO)  

2.OQ 

Magnesia  (MgO)  

2.O 

Potash  (K2O)  

4.06 

Soda  (Na2O) 

2    2C 

Ignition  (H2O)  

4.60 

99.62 

The  appearance  of  the  Lewiston  clay  under  the  microscope  is 
shown  in  Plate  XXIII,  Fig.  2. 

Leda  clays  from  Beaver  County,  Pennsylvania,  used  in  the 
manufacture  of  terra  cotta  at  New  Brighton,  are  reported  l  as  having 
the  following  composition s 


1  Second    Geological    Survey  of    Pennsylvania,   Report  of  Chemical    Analyses 
P-  257- 


234 


THE  NON-METALLIC   MINERALS. 


Constituents. 
Silica...  1  

Percei 

46.160 
26.976 
7.214 
.740 

2.210 
1.520 
3.246 
11.220 

itages. 

67.780 
16.290 

4-570 
.780 
,  .600 
.727 

2.0OI 
6.340 

Alumina  

Sesouioxide  of  iron 

Titanic  acid 

Lime  

Magnesia 

Alkalies 

Water  

Total  

90.286 

99.088 

Vitrified  brick  for  street  pavements  are  made  from  fusible  clays, 
sometimes  in  their  natural  condition  and  sometimes  mixtures  of 
ground  shale  and  clay. 

The  following  analyses  are  given  of  the  materials  used  by  the 
Onondaga  Vitrified  Pressed  Brick  Company,  of  New  York:1 


Constituents. 

Calcareous 
layer  in 
shale  bank. 

A  green 
brick; 
being  a 
mixture  of 
the  differ- 
ent shales. 

Red  shale. 

Blue  shale. 

Clay. 

'S'Hca 

2  s  4.O 

^4.  2  ? 

C2   3O 

^7  70 

4X  3^ 

Alu'nina. 

94.6 

1680 

3*'j>w 

18  8? 

i/'/y 
16.1^ 

12   10 

Peroxide  of  iron   

2.24 

V 

<.8i 

iO.O^ 

6.  CC 

S.2O 

4.41 

Lime  

22.8l 

4.74 

«**O3 

•?.^6 

2.7'? 

IO.QQ 

Magnesia 

IO  3O 

521 

A    AQ 

4.  67 

6  ^8 

Carbonic  acid 

20  96 

4  3O 

•}   O4. 

3.  4.2 

7  24. 

Potash 

.CK 

2  OX 

4.6? 

4-II 

3.26 

Soda   .                                    .    .. 

I.7C 

1.22 

1.  14. 

Water  and  organic  matter  
Oxide  of  manganese 

7.60 

5.01 

5-30 

Trace 

4-50 

Trace 

8.90 

Total 

00.81 

00  ^0 

oo  80 

QQ.7Q 

oo  86 

(6)  The  name  slip  clay  is  given  to  a  readily  fusible,  impalpably 
fine  clay  used  for  imparting  a  glaze  to  earthenware  vessels.  These 
clays  carry  iron  oxides,  potash,  and  soda,  together  with  lime  and 
magnesia,  in  such  proportions  that  they  vitrify  readily,  forming 
thus  an  impervious  glass  over  those  portions  of  the  ware  to  which 
they  are  applied. 

The  following  analyses  show  (I)  the  composition  of  a  slip  clay 
used  in  pottery  works  in  Akron,  Ohio,  and  (II)  one  from  Albany, 
New  York: 


Bulletin  of  the  New  York  State  Museum,    III,  No.    12,   March,   1895.     Clay 
Industries  of  New  York,  p.  200. 


SILICATES. 


235 


Constituents. 

I. 

II. 

Silica  

60.40 

c8.S4 

Alumina  

10.42 

1^.41 

Iron  sesauioxide  

5.l6 

3-10 

Ijime 

g  88 

6  ^o 

Magnesia 

4  28 

•7    AQ 

Alkalies.  . 

o  87 

A     A? 

Sulphuric  acid 

o  6^ 

I     IO 

Phosphoric  acid 

O  OQ 

Carbonic  acid  and  water.    .    . 

8  oq 

8  08 

Total  

IOO.OO 

100  47 

The  Albany  clay  is  stated  by  Nason  *  to  glaze  at  comparatively 
low  temperatures  and  to  rarely  crack  or  check.  It  occurs  in  a 
stratum  4  to  5  feet  thick.  It  is  used  very  extensively  in  the  United 
States,  and  has  even  been  shipped  to  Germany  and  France. 

(7)  The  name  adobe  is  given  to  a  calcareous  clay  of  a  gray-brown 
or  yellowish  color,  very  fine  grained  and  porous,  which  is  sufficiently 
friable  to  crumble  readily  in  the  fingers,  and  yet  has  sufficient  coher- 
ency to  stand  for  many  years  in  the  form  of  vertical  escarpments, 
without  forming  appreciable  talus  slopes.  It  is  in  common  use 
throughout  Arizona,  New  Mexico,  and  Mexico  proper  for  building 
material,  the  dry  adobe  being  first  mixed  with  water,  pressed  in 
rough  rectangular  wooden  molds  some  10  by  18  or  more  inches  and 
3  or  4  inches  deep,  and  then  dried  in  the  sun.  In  some  cases  chopped 
straw  is  mixed  with  it  to  increase  its  tenacity.  Buildings  formed 
of  this  material  endure  for  generations  and  even  centuries  in  arid 
climates.  The  material  of  the  adobe  is  derived  from  the  waste  of 
the  surrounding  mountain  slopes,  the  disintegration  being  mainly 
mechanical.  According  to  Prof.  I.  C.  Russell  it  is  assorted  and 
spread  out  over  the  valley  bottoms  by  ephemeral  streams.  It  con- 
sists of  a  great  variety  of  minerals,  among  which  quartz  is  con- 
spicuous. The  chemical  nature  of  the  adobes  varies  widely,  as 
would  naturally  be  expected,  and  as  is  shown  in  the  following 
analyses  from  Professor  Russell's  paper:2 


1  Forty-seventh  Annual  Report  of  the  State  Geologist  of  New  York,  1893,  p.  468. 

2  Subaerial  Deposits  of  North  America,  Geological  Magazine,  VI,  1889,  pp.  289 
and  342. 


236 


THE  NON-METALLIC  MINERALS. 

ANALYSES    OF   ADOBE. 


Constituents. 

I. 
Santa  Fe, 
New 
Mexico. 

II. 
Fort  Win- 
gate,  New 
Mexico. 

III. 

Humboldt, 
Nevada. 

IV. 
Salt  Lake 
City,  Utah. 

SiO  .  . 

66  69 

, 

Al  (X.  . 

14  16 

19.24 

7    06 

Fe,O,.  . 

A     7g 

o  64 

3-^u 

MnO  

o  oo 

Trace 

•" 

i.uy 

Trace 

CaO  

2  4.Q 

36  AO 

u.i^ 

T  7    QT 

78  OA 

M>O 

I  28 

K,O   . 

I   21 

Trace 

^.yu 

2-75 
Trace 

Na,O.  . 

o  61? 

Trace 

*•/* 

Trace 

CO,.. 

O  77 

2=C  8d 

u-c>V 

8  cc 

p,o  

O  2Q 

O  7  r 

°oo 

•"VO/ 

SO 

o  82 

v.^ 

Cl.  . 

O  7.J. 

°-53 

H,O.  . 

d.  Qd. 

2  26 

7.  SA 

i  67 

Organic  matter. 

2  OO 

5  jo 

O-°4 

•7     ,1-7 

l.U/ 

6-^6 

Total  

OQ.72 

QQ    Q7 

OO  7O 

TOO    1Z 

JW'O5 

(8)  The  name  loess  is  given  to  certain  Quaternary  surface  de- 
posits closely  simulating  adobe,  but  concerning  the  origin  of  which 
there  has  been  considerable  dispute.  Deposits  in  the  United  States 
are,  according  to  the  best  authorities,  or  subaqueous  origin.  Clays 
of  this  nature  are,  as  a  rule,  higher  in  silica  than  the  adobes  and 
correspondingly  poorer  in  alumina.  Loess  is  a  common  surface 
deposit  throughout  the  Mississippi  Valley,  and  is  in  many  instances 
of  such  consistency  as  to  be  utilized  for  brickmaking. 

The  analyses  given  on  p.  237  are  from  Professor  Russell's  paper. 

Properties  of  Clays. — The  cause  of  the  peculiar  properties  of 
clays,  particularly  those  of  plasticity  and  induration,  cannot  as 
yet  be  said  to  have  been  fully  explained.  Various  explanations 
have  been  made  with  reference  to  plasticity,  but  none  which  have 
proven  to  be  conclusive.  It  has  been  ascribed  to  the  alumina, 
to  the  combined  water  and  the  shape  and  size  of  the  constituent 
particles  and  to  the  presence  of  colloidal  matter,  but  no  one 
quality  seems  to  cover  all  cases,  and  in  the  end  it  will  probably 
be  shown  that  there  are  many  phases  of  plasticity  due  perhaps 
to  as  many  causes.  Cook  thought  to  show l  that  some  of 
the  non-plastic  clays  which  become  plastic  on  kneading  were 


Report  oh  Clay  Deposits,  Geological  Survey  of  New  Jersey. 


SILICATES. 


237 


ANALYSES   OF   THE   LOESS   OF  THE   MISSISSIPPI   VALLEY. 


Constituents. 

No.  i. 

No.  2. 

No.  3. 

No.  4. 

SiO 

72.68 

64.61 

74.46 

6o.6g 

A1O  .  . 

12.03 

10.64 

12.26 

7-0^ 

FeO.. 

^.C'J 

2.61 

3-2< 

2.61 

FeO.3     ' 

0.06 

O.SI 

O.I2 

0.67 

TiO,  

0.72 

0.40 

O.I4 

O.S2 

P.O.. 

O.2T. 

0.06 

O.OQ 

O.I? 

MnO  

O.O6 

o.os 

O.O2 

O.I2 

CaO  

I.^Q 

1^.41 

1.69 

8.06 

MffO   . 

I.  II 

3.69 

1.  12 

4.^6 

Na,O  

1.68 

I.2C 

1.4? 

1.  17 

K9O.  . 

2.13 

* 

2.06 

1.83 

i.  08 

H..O  

C12.Z.O 

a2.o^ 

Q2.70 

fli.14 

CO 

O.3Q 

6.11 

o  40 

967 

SO 

O.SI 

O.II 

0.06 

O  12 

c  3  

O.OQ 

O.I3 

O.I2 

O  IQ 

Total 

IOO.2I 

00-00 

00.78 

00.^4. 

a.  Contains  H  of  organic  matter,  dried  at  100°  C. 

composed  of  masses  of  hexagonal  plates  or  scales  piled  up  in  long 
bundles,  and  that  the  kneading  necessary  to  produce  plasticity  broke 
up  the  bundles  leaving  a  homogeneous  matrix  of  crushed  material 
derived  therefrom.  Subsequent  investigation  has,  however,  failed 
to  confirm  this  view.  The  presence  of  combined  water  has  un: 
doubtedly  some  effect,  since  clays  so  highly  heated  as  to  drive  off  this 
water  are  no  longer  plastic.  The  alumina  alone  cannot  be  the 
cause,  otherwise  kaolin  would  be  one  of  the  most  plastic  of  clays, 
which  is  far  from  being  the  case.  Moreover  there  are  other  hydrous 
aluminum  compounds  which  are  not  plastic  in  the  least.  Accord- 
ing to  certain  Russian  authorities  plasticity  is  due  not  only  to  the 
interlocking  of  clay  particles  but  varies  with  the  texture,  the  ex- 
tremely coarse  and  fine  varieties  being  less  plastic  than  the  inter- 
mediate forms.  This  view  has,  in  the  past,  been  held  by  Dr.  H. 
Ries  and  H.  A.  Wheeler.1  H.  Rosier  2  regards  plasticity  as  due  to 
the  flattened  form  of  the  constituents,  their  softness  and  their  fine- 
ness, and  there  is  much  to  support  this  view. 


1  Clay  Deposits  and  Clay  Industry  in  North  Carolina,  Bulletin  No.  13,  North 
Carolina  Geological  Survey,  1897.  See  also  Clays,  Occurrences,  Properties,  and  Uses* 
1906. 

1  Neues  Jahrb.  fur  Min.  u.  Paleon.,  Beilage-Band,  2.  Heft,  Vol.  XV,  1902. 


238  THE  NON-METALLIC  MINERALS. 

So  far  as  the  compiler's  own  observations  go,  plasticity  is  not 
dependent  wholly  upon  hydration  nor  size  nor  shape  of  the  constit- 
uent particles.  The  glacial  (Leda)  clays  are  made  up  of  fresh, 
sharply  angular  particles  of  various  minerals  and  contain  less  than 
5  per  cent  combined  water;  yet  in  their  natural  condition  they  are 
extremely  plastic,  and  scarcely  less  so  when  mixed  with  two-fifths 
their  bulk  of  ordinary  siliceous  sand,  as  is  done  in  the  process  of 
brickmaking.  The  Albany  County,  Wyoming,  clay,  on  the  other 
hand,  equally  or  even  more  plastic  and  exceedingly  pasty,  is  made 
up  of  extremely  minute  particles  of  fairly  uniform  size,  scarcely 
angular,  and  apparently  all  of  the  same  mineral  (colloidal)  nature 
throughout.  This  yields  some  16  per  cent  of  water,  on  ignition,  as 
shown  in  analysis,  p.  247.  On  the  whole,  the  evidence  seems  to 
show  that  the  plasticity  is  due  to  the  manner  in  which  the  particles 
conduct  themselves  toward  moisture,  and  this  is  apparently  de- 
pendent upon  the  size  and  shape  and  the  proportional  admixture 
of  varying  sizes  of  the  constituents  rather  than  upon  their  chemical 
composition.  The  colloidal  nature  of  the  constituents  of  certain 
clays  is  undoubtedly  an  important  factor.1 

The  expulsion  of  the  absorbed  and  combined  water  in  a  clay  is 
nearly  always  accompanied  by  a  diminution  in  volume,  which  varies 
directly  as  the  water,  or  the  purity  of  the  clay.  Pure  kaolin  shrinks 
as  much  as  one-fourth  of  its  bulk,  it  is  stated,  sometimes  even 
more.  The  sandy  clays  used  in  making  sewer-pipe  and  stoneware 
shrink  in  the  tempered  state  from  one-ninth  to  one-sixteenth,  usually 
about  one- twelfth. 

A  clay,  when  all  the  water  of  crystallization  is  expelled,  will  not 
shrink  any  more  at  red  heat,  but  with  increased  heat  will  continue 
to  shrink  up  to  the  moment  of  fusion.  A  pure  kaolin  apparently 
shrinks  when  heated  a  second  time,  even  if  the  water  is  all  expelled 
by  the  first  heat,  yet  it  is  practically  impossible  to  fuse  it.  But  a 
good  flint  clay  containing  some  sand  will  lose  all  shrinkage  on  being 
once  calcined  at  white  heat.  Such  clay  is  then  used  to  counteract 
shrinkage  in  a  body  of  green  clay,  as  is  also  siliceous  sand.  Many 


1  See  The  Colloidal  Matter  of  Clay  and  Its  Measurement,  Bulletin  No.  388,  U.  S. 
Geological  Survey,  1909. 


SILICATES.  239 

clays  contain  sand  enough  naturally  and  some  are  so  sandy  as  to 
actually  expand  on  heating,  though  usually  at  the  expense  of  sound- 
ness of  structure;  for  the  particles  of  clay  will  shrink  away  from 
the  grains  of  sand,  rendering  the  product  very  friable. 

The  refractory  or  fire-proof  property  of  clay  depends  largely 
upon  the  alumina  and  silica,  and  their  freedom  from  all  constituents 
which  are  fusible  in  themselves  or  which  would  combine  with  others 
to  form  a  flux.  Pure  alumina,  or  pure  quartz  alone,  is  practically 
infusible.  The  constituents  tending  to  make  a  clay  fusible  are 
iron,  soda,  potash,  lime,  and  magnesia.  Which  of  these  is  the  more 
detrimental  it  would  be  difficult  to  say.  Iron  is  not  so  powerful 
a  flux  as  either  potash  or  soda;  but  on  the  other  hand  it  is  much 
more  abundant,  and  may  moreover  impart  an  unsatisfactory  color. 

The  extent  to  which  iron  may  be  present  without  detriment 
is  a  point  on  which  authorities  do  not  agree.  The  Stourbridge 
clay  of  England  has  2.25  per  cent  of  iron,  with  extremes  of  1.43  and 
3.63  per  cent.  Gros  Almerode  clay  has  2.12;  Coblentz,  2.03;  New 
Castle,  2.32,  and  yet  all  these  are  famous  fire  clays.  Test  mixtures 
of  iron  and  pure  kaolin  have  been  run  higher  than  this  and  have 
stood  well,  but  as  a  general  rule  it  is  unsafe  to  rely  for  fire  qualities 
on  a  clay  with  over  2  per  cent  of  iron,  particularly  if  the  other  im- 
purities are  developed  in  any  amount.  It  is  a  well-known  principle 
in  chemistry  that  mixtures  of  bases  are  much  more"  active  fluxes 
than  an  equal  amount  of  any  one  base;  so  with  iron,  its  effect  shows 
worse  when  in  presence  of  other  fluxing  agents. 

The  condition  of  the  iron,  whether  as  a  sesquioxide  or  protoxide 
is  also  an  important  matter,  the  latter  form  only,  it  is  stated,  being 
likely  to  combine  with  the  silica,  to  form  silicates. 

Sulphide  of  iron  has  a  bad  effect,  since  its  decomposition  gives 
rise  to  the  lower  oxide;  the  effect  which  the  sulphur  may  have  must 
also  receive  consideration.  Iron  in  the  uncombined  state  imparts 
to  a  piece  of  ware  a  buff  or  red  color;  when  combination  begins 
and  progresses  the  ware  becomes  of  a  bluish-gray  cast,  deepening 
as  the  fusion  of  the  iron  proceeds,  and  finally  becoming  glassy  black 
if  much  iron  is  present. 

In  any  but  the  glacial  clays  the  comparatively  small  amounts 
of  lime  and  magnesia  present  causes  them  to 'be  but  little  thought 


240  THE  NON-METALLIC  MINERALS. 

of  as  detrimental.  They  occur  both  as  silicates  and  carbonates. 
When  present  as  carbonates  they  combine  at  a  higher  temperature 
than  is  required  for  iron  or  potash.  The  Milwaukee  brick  clays, 
as  already  noted,  carry  considerable  amounts  of  carbonates  of  lime 
and  magnesia,  and  require  a  very  hot  burn,  but  when  once  the  lime 
and  silica  combine  they  destroy  the  effect  of  5  per  cent  of  iron,  and 
impart  a  cream  color.  A  brick  of  this  kind  presents  an  even,  fine- 
grained, vitrified  appearance  on  its  fracture.1 

The  amount  of  potash  which  a  clay  may  contain  and  keep  its  fire 
properties  is  variously  put  by  different  authorities.  As  with  iron, 
kaolin  will  stand  a  good  deal  when  no  other  base  is  present,  but  a 
multiplicity  of  bases  makes  fusion  easy.  Titanic  acid  in  the  form 
of  ilmenite  or  rutile,  is  regarded  as  neutral  to  fire  qualities,  being 
itself  practically  infusible. 

Testing  clays. — Knowing  the  effect  of  the  various  constituents  in 
promoting  fusion  or  imparting  color  changes  it  might  at  first  thought 
seem  that  chemical  analyses  would  serve  to  indicate  the  uses  to  which 
any  clay  was  best  adapted.  In  practice,  however,  it  is  not  customary 
to  rely  wholly  on  analyses,  but  rather  to  couple  them  with  special 
tests  made  to  ascertain  their  strength  and  fire-resisting  properties. 
Fire  tests  are  of  two  kinds — one  consists  in  subjecting  the  clay 

1  They  (lime  and  magnesia)  have  also  the  remarkable  property  of  uniting  with  the 
iron  ingredient  to  form  a  light-colored  alumina-lime-magnesia-iron  silicate,  and  thus 
the  product  is  cream-colored  instead  of  red.  Mr.  Sweet  has  shown  by  analysis  that 
the  Milwaukee  light-colored  brick  contain  even  more  iron  than  the  Madison  red 
brick.  At  numerous  points  in  the  Lake  region  and  in  the  Fox  River  valley  cream- 
colored  brick  are  made  from  red  clays.  In  nearly  or  quite  all  cases,  whatever  the 
original  color  of  the  clay,  the  brick  are  reddish  when  partially  burned.  The  explana- 
tion seems  to  be  that  at  a  comparatively  moderate  temperature  the  iron  constituent 
is  deprived' of  its  water  and  fully  oxidized,  and  is  therefore  red,  while  it  is  only  at 
a  relatively  high  heat  that  the  union  with  the  lime  and  magnesia  takes  place,  giving 
rise  to  the  light  color.  The  calcareous  and  magnesian  clays  are,  therefore,  a  valuable 
substitute  for  true  aluminous  clays,  for  they  not  only  bind  the  mass  together  more 
firmly,  but  give  a  color  which  is  very  generally  admired.  They  have  also  this  practical 
advantage,  that  the  effects  of  inadequate  burning  are  made  evident  in  the  imperfect 
development  of  the  cream  color,  and  hence  a  more  carefully  burned  product  is  usually 
secured.  It  is  possible  to  make  a  light-colored  brick  from  a  clay  which  usually  burns 
red  by  adding  lime.  The  amount  of  lime  and  magnesia  in  the  Milwaukee  brick  is 
about  25  per  cent.  In  the  original  clays  in  the  form  of  carbonates  they  make  up  about 
40  per  cent.  (Geology  of  Wisconsin,  I,  1873-79,  p.  669.) 


SILICATES.  241 

to  absolute  heat  without  the  action  of  any  accompaniments,  and 
the  other  in  putting  the  clay  through  the  course  of  treatment  for 
which  it  is  designed  to  be  used.  The  former  develops  the  absolute 
quality  of  the  clay  as  good  or  bad,  the  latter  proves  or  disproves 
the  fitness  of  the  clay  for  any  particular  work.  The  latter  is  better 
of  course  as  a  business  test  wherever  it  is  practicable  to  use  it.  The 
former  can  be  made  only  in  a  specially  adapted  furnace.  The  clay 
in  this  test  is  cut  into  one-inch  cubes  with  square  edges,  and  is  set 
in  a  covered  crucible  resting  on  a  lump  of  clay  of  its  own  kind,  so 
that  it  touches  no  foreign  object.  The  heat  is  then  applied,  and 
its  effect  will  vary  from  fusing  the  mass  to  a  button  to  leaving  it 
with  edges  sharp  and  not  even  glazed  on  the  surface.  Experience 
soon  renders  one  proficient  in  judging  of  clays  by  this  test.1 

A  method  of  testing  the  fusibility  of  clays  by  comparing  them 
with  samples  of  known  composition  and  fusibility  has  of  late  years 
come  into  extensive  use.  These  prepared  samples,  known  from 
their  inventor  and  their  shape  as  Seger's  pyramids,  or  cones,  consist 
of  mixtures  in  varying  proportions  of  kaolin  and  certain  fluxes,  so 
prepared  that  there  is  a  constant  difference  between  their  fusing 
points.  When  such  cones,  together  with  the  samples  to  be  tested, 
are  placed  in  a  furnace  or  kiln,  they  begin  to  soften  as  the  tem- 
perature is  raised,  and  as  it  approaches  their  fusion  points  the 
cones  bend  over  until  the  tip  is  as  low  as  the  base.  When  this 
occurs  the  temperature  at  which  they  fuse  is  considered  to  have 
been  reached.2 

Uses. — Clay  when  moistened  with  water  is  plastic  and  suf- 
ficiently firm  to  be  fashioned  into  any  form  desired.  It  can  be 
shaped  by  the  hands  alone;  by  the  hands  applied  to  the  clay  as 
it  turns  with  the  potter's  wheel,  or  it  can  be  shaped  by  molds, 
presses,  or  tools.  When  shaped  and  dried,  and  then  burned  in 
an  oven  or  kiln,  it  becomes  firm  and  solid,  like  stone;  water  will 
not  soften  it,  it  has  entirely  lost  its  plastic  property,  and  is  per- 
manently fixed  in  its  new  forms,  and  for  its  designed  uses.  These 

1  Geological  Survey  of  Ohio,  Economic  Geology,  V,  pp.  652-655. 

2  See  Dr.  Ries's  paper  on  North  Carolina  clays,  already  quoted,  and  also  his 
numerous  contributions  on  their  subject  in  the  volumes  of  the  United  States  Geolog- 
ical Survey  relating  to  mineral  statistics. 


242  THE  NON-METALLIC  MINERALS. 

singular  and  interesting  properties  are  possessed  by  clay  alone, 
and  it  is  to  these  it  owes  its  chief  utility.  It  is  used  (i)  for  making 
pottery;  (2)  for  making  refractory  materials;  (3)  for  making  build- 
ing materials;  (4)  for  miscellaneous  purposes. 

Pottery. — Clay  worked  into  shapes  and  burned  constitutes 
earthenware.  The  ware  of  itself  is  porous,  and  will' allow  water 
and  soluble  substances  to  soak  through  it.  To  make  it  hold 
liquids,  the  shaped  clay  before  burning  is  covered  with  some  sub- 
stance that  in  the  burning  of  the  ware  will  melt  and  form  a  glass 
coating  or  glazing  which  will  protect  the  ware,  and  give  it  a  clean, 
smooth  surface.  The  color  of  the  ware  depends  on  the  nature  of  the 
clay.  Clays  containing  oxide  of  iron  burn  red,  the  depth  of  color 
depending  on  the  amount  of  the  oxide,  even  a  small  fraction  of  i  per 
cent  being  sufficient  to  give  a  buff  color. 

Clay  containing  oxide  of  iron  in  sufficient  quantity  to  make  it 
partially  fusible  in  the  heat  required  to  burn  it  is  called  stoneware 
clay.  The  heat  is  carried  far  enough  to  fuse  the  particles  together 
so  that  the  ware  is  solid  and  will  not  allow  water  to  soak  through 
it;  but  not  so  far  as  to  alter  the  shapes  of  the  articles  burned.  The 
oxide  of  iron  by  the  fusion  combines  with  the  clay,  and  instead 
of  its  characteristic  red,  gives  to  the  ware  a  bluish  or  grayish 
color. 

Clay  which  is  white  in  color  and  entirely  free  from  oxide  of  iron 
may  be  intimately  mixed  with  ground  feldspar  or  other  minerals 
which  contain  potash  enough  to  make  them  fusible,  and  the  mixture 
still  be  plastic  so  as  to  be  worked  into  forms  for  ware.  When  burned, 
such  a  composition  retains  its  white  color,  while  it  undergoes  fusion 
sufficient  to  make  a  body  that  will  not  absorb  water.  Ware  of  this 
kind  is  called  porcelain  or  china. 

Refractory  materials. — Modern  improvements  in  metallurgy, 
and  furnaces  for  many  other  industrial  purposes,  are  dependent 
to  a  great  degree  on  having  materials  for  construction  which  will 
withstand  intense  heat  without  fusing,  cracking,  or  yielding  in  any 
way.  The  two  materials  to  which  resort  is  had  in  almost  all  cases  are 
pure  aluminous  clay,  and  quartz  in  the  form  of  sand  or  rock.  They 
are  both  infusible  in  any  but  the  very  highest  furnace  heats.  A  clay, 
however,  is  liable  to  have  in  it  small  quantities  of  fusible  constituents 


SILICATES.  243 

and  to  shrink  when  heated  to  a  high  temperature.  Quartz  rocks 
are  liable  to  crack  to  pieces  if  heated  too  rapidly,  and  both  the 
rocks  and  sand  are  rapidly  melted  when  in  contact  with  alkaline 
earths,  or  metallic  oxides,  at  a  high  temperature.  They  do  not, 
however,  shrink  in  heating.  Brjcks  to  resist  intense  heat  are  made 
of  clay,  of  sand,  or  of  a  mixture  of  clay  and  sand.  The  different 
kinds  are  specially  adapted  to  different  uses. 

To  make  fire  bricks  a  clay  which  stands  an  intense  heat  is  se- 
lected. This  is  tempered  so  that  it  may  not  shrink  too  much  or 
unevenly  in  burning,  by  adding  to  the  raw  clay  a  portion  of  clay 
which  has  been  burned  till  it  has  ceased  to  shrink  and  then  ground, 
or  a  portion  of  coarse  sand,  or  a  quantity  of  feldspar.  These  ma- 
terials are  added  in  the  proportions  which  the  experience  of  the 
manufacture  has  found  best.  The  formula  for  the  mixture  is  the 
special  property  of  each  manufacturer,  and  is  not  made  public.  The 
materials,  being  mixed  together  and  properly  wet,  are  molded  in 
the  same  way  as  common  bricks,  and  after  they  have  dried  a  little 
they  are  put  into  a  metallic  mold  and  subjected  to  powerful  pressure. 
They  are  then  taken  out,  dried,  and  burned  in  a  kiln  at  an  intense 
heat. 

It  does  not  appear  which  is  the  best  for  tempering,  burned  and 
ground  clay,  or  coarse  sand,  or  feldspar.  Reputable  manufacturers 
are  found  who  use  each  of  these  materials,  and  make  brick  that 
stand  fire  well. 

Fire  bricks  intended,  in  addition  to  their  refractory  qualities,  to 
retain  their  size  and  form  under  intense  heat  without  shrinkage, 
have  been  made  to  some  extent.  The  English  Dinas  bricks  are 
of  this  kind,  and  the  German  and  French  " silica  bricks."  The 
Dinas  bricks  are  of  quartz  sand  or  crushed  rock,  and  contain  very 
little  alumina  and  about  i  per  cent  of  lime.  They  stand  fire  re- 
markably well,  the  lime  causing  the  grains  of  sand  to  stick  together 
when  the  bricks  are  intensely  heated.  In  the  other  "  silica  bricks," 
fire  clay  to  the  amount  of  5  or  10  per  cent  is  mixed  with  the 
sand,  the  plastic  material  causing  the  particles  of  sand  to  cohere 
sufficiently  to  allow  handling  before  burning. 

Paper  clay. — Clay  which  is  pure  white  and  that  also  which  is 
discolored  and  has  been  washed  to  bring  it  to  a  uniform  shade  of 


244  THE  NON-METALLIC  MINERALS 

color,  is  used  by  the  manufacturers  of  paper  hangings,  to  give  the 
smooth  satin  surface  to  the  finished  paper.  It  is  used  by  mixing  it 
up  with  a  thin  size,  applying  it  to  the  surface  of  the  paper,  and 
then  polishing  by  means  of  brushes  driven  by  machinery.  The 
finest  and  most  uniformly  colored  clays  only  are  applicable  to  this 
use,  and  they  are  selected  with  great  care.  Clay  is  also  used  to 
give  body  and  weight  to  paper.  Heavy  wrapping  paper,  such  as 
is  used  by  the  United  States  Post-office  Department,  must,  according 
to  specifications,  contain  95  per  cent  of  jute  butts  and  5  per  cent  of 
clay.  The  cheaper  forms  of  confectionery  are  very  heavily  adulter- 
ated with  this  material. 

Alum  clay. — A  large  quantity  of  clay  is  used  for  making  alum. 
A  rich  clay  is  needed  for  this  purpose. 

The  white  clay  of  Gay  Head  and  Chilmark,  Martha's  Vineyard, 
Massachusetts,  was  at  one  time  used  extensively  for  alum-making, 
according  to  Edward  Hitchcock.1 

As  a  substitute  for  sand  in  making  mortar  and  concrete,  clay  is 
perhaps  the  best  material  to  be  found.  For  this  purpose  the  clay  is 
burnt  so  that  it  is  produced  in  small  irregular  pieces  that  are  very 
hard  and  durable.  These  pieces  are  then  ground  to  a  fairly  fine 
powder,  which  is  mixed  with  the  lime  or  cement  as  sand  would  be. 
The  result  is  a  very  strong  mortar,  in  some  cases  stronger  than  when 
sand  is  employed.2 

The  so-called  gumbo  clays,  sticky,  tough,  and  dark-colored 
clays  of  the  Chariton  River  region,  Missouri,  are  hard  burned  and 
used  for  railroad  ballast  and  macadam. 

Under  the  names  of  Rock  Soap  and  Mineral  Soap  there  have  from 
time  to  time  been  described  varieties  of  clay  which,  owing  to  their 
feeling,  are  suggestive  of  soap,  and  which  in  a  few  instances  have 
been  actually  used  in  the  prparation  of  this  material. 

A  rock  soap  from  Ventura  County,  California,  has  been  described 
by  Prof.  G.  H.  Koenig  as  a  mixture  of  sandy  and  clayey  or  soapy 
material  in  the  proportion  of  45  per  cent  of  the  first  and  55  per  cent 
of  the  second.  The  chemical  composition  of  the  material  and  of 
the  two  portions  is  given  below : 

1  American  Journal  of  Science,  XXII,  1832,  p.  37. 
3  The  World's  Progress,  February,  1893. 


SILICATES. 


Constituents. 

Crude 
material. 

Sandy 
portion. 

Soapy 
portion 

Silica. 

67  <  ^ 

Alumina,  and  iron 

12  Q7 

I  3  ?O 

/o  1U 

Lime 

O  77 

O  3O 

"1 

Magnesia     . 

o  8< 

Trace 

!  Not  de 

Potash  

u.o5 

I    AT.    1 

ter- 

Soda  

1   6l    \ 

4-55 

mined. 

Water  

I  ^   67 

I  2  2  N 

Nearly  all  the  silica  is  in  a  soluble  or  opalescent  state 
and  the  alumina  either  a  hydrate  or  very  basic  silicate.  It 
is  said1  that  at  one  time  the  material  was  made  into  a  variety  of 
useful  articles,  as  "salt  water  soap,"  scrubbing  and  toilet  soap, 
tooth  powder,  etc. 

A  somewhat  similar  material  from  Elk  County,  Nevada,  has 
been  used  for  like  purposes,  and  put  upon  the  market  under  the 
name  of  San-too-gah-choi  mineral  soap.  This  clay  is  of  a  drab 
color,  with  a  slight  pinkish  tint,  a  pronounced  soapy  feeling  and 
slight  alkaline  reaction  when  moistened  and  placed  upon  test  paper. 
An  analysis  by  R.  L.  Packard  in  the  laboratory  of  the  U.  S.  National 
Museum  yielded: 


Constituents. 

Per  Cent. 

Silica 

48  80 

Alumina                   .  .            

18   <7 

Iron  oxides               

T,  88 

Lime          

i  07 

Magnesia  

2    <2 

Soda     

2.32 

Potash  

I    12 

Ignition  

21    13 

Total  

00  41 

Mention  may  be  made  here  also  of  the  material  sold  in  the  shops 
under  the  name  of  Bon  Ami,  and  used  for  cleansing  glass  and  other 
like  substances.  This  under  the  microscope  shows  abundant  mi- 


1  Sixth  Annual  Report  of  the  State  Mineralogist  of  California,  1886,  Pt.  i,  p.  132. 


246 


THE    NON-METALLIC   MINERALS. 


nute  sharply  angular  particles,  consisting  of  partially  decomposed 
feldspar  mixed  with  a  completely  amorphous  mineral  which  may 
be  opalescent  silica  or  possibly  a  very  finely  comminuted  pumice. 
An  analysis  by  R.  L.  Packard  yielded : 


Constituents. 

Per  Cent. 

Silica  

ZQ  86 

Alumina  

l8    74 

Magnesia  

O    34 

Potash  

IO   7O 

Soda 

Ignition 

O  A 
7    67 

/  •"/ 

Total 

100  82 

Alcohol  extracts  7.43  per  cent,  and  water  0.244  per  cent  in  addi- 
tion, the  extract  having  a  soapy  appearance  and  the  odor  of  some 
essential  oil. 

A  peculiar  soapy  clay  found  in  Albany,  Crook,  Weston,  and 
Natrona  Counties,  Wyoming,  has  been  shipped  in  considerable 
quantities  during  the  past  few  years  to  Philadelphia,  New  York, 
and  Chicago,  where  it  was  sold  under  the  name  of  Bentonite  at 
prices  varying  from  $5.00  to  $25.00  per  ton.  It  is  stated  l  to  have 
been  used  in  paper  manufacture,  as  a  packing  for  horses'  feet;  for 
a  time  as  a  soap  in  one  of  the  local  railway  hotels,  and  in  the  mak- 
ing of  "antiphlogistine,"  a  substance  widely  used  in  the  West  in  the 
form  of  a  plaster  applied  to  the  chest  in  cases  of  pneumonia  or 
croup.  It  has  been  suggested  as  admirably  suited  for  use  as  a 
"retarder"  for  the  hard-finish  plasters  now  coming  into  use  for 
walls. 

This  clay  is  regarded  by  T.  B.  Read  as  originating  through  the 
decomposition  of  the  feldspar  labradorite  occurring  in  the  anor- 
thosite  of  the  Laramie  Mountains.  The  chief  physical  charac- 
teristic, aside  from  its  soapy  feeling,  is  its  enormous  absorptive 
power,  the  absorption  being  attended  naturally  with  an  increase 


1  Engineering  and  Mining  Journal,  LXIII,  1897,  p.  600,  LXVI,  1898,  p.  491,  and 
LXXYI,  1903,  P-  48. 


SILICATES. 


247 


in  bulk  amounting  to  several  times  that  of  the  original  mass.2  Plate 
XXV,  Fig.  i,  shows  the  extreme  fineness  and  homogeneity  of  this 
clay  as  seen  under  the  microscope. 

The  reported  analyses  are  as  follows : 


Constituents. 

I. 

Rock 
Creek. 

II. 
Crook 
County. 

III. 
Western 

County. 

IV. 

Natrona 
County. 

SiO2  

^0.78 

61.08 

6T..2Z 

6^.24 

Al  CX.  , 

Is.IO 

17.12 

12.62 

15.88 

FeO, 

2.40 

3-17 

3.70 

?.I2 

MgO 

4.14 

1.82 

3-7o 

c.?4 

CaO.                       .    . 

0.73 

2.60 

4.12 

C.?4 

Na  O,K  O. 

(a) 

bo.  20 

(a) 

SO 

(a) 

0.88 

I.C7 

(a) 

H  O 

16.26 

O.I7 

Specific  gravitv. 

2.132 

a.  No  estimate. 


b.  NaO. 


The  analyses  given  on  the  following  pages,  compiled  from  works 
believed  to  be  authoritative,  show  the  varying  character  of  clays, 
so  far  as  their  chemical  composition  is  concerned.  In  many  of 
these  analyses,  it  will  be  observed,  the  silica  existing  in  the  form 
of  quartz  is  given  a  separate  column  from  that  combined,  while 
in  column  4  is  given  the  calculated  percentage  of  kaolin  which  the 
analyses  seem  to  indicate  each  sample  contains. 


1  A  small  plug  of  this  clay  fitted  to  accurately  occupy  a  space  of  20  cubic  centi- 
meters in  the  bottom  of  a  conical  measuring-flask,  and  kept  saturated  with  water  for 
two  days,  swelled  to  a  bulk  of  160  cubic  centimeters.  The  absorption  was  so  com- 
plete that  none  of  the  water  ran  off  when  the  flask  was  inverted,  and  the  condition 
of  the  clay  resembled  that  of  flour  or  starch  paste. 


248 


NON-METALLIC  MINERALS. 


T*VM,  mnS     £ 

M          VO            t- 

oo       H      oo 

000 
000 

\O         0              0         «         O        vOOO 
00        O              O       ID       T}-       to  O 

o     d          d     oo      o     o'  d 
o     o          o      o     o     o  o 

••HWH     « 

H      d       • 

*f       Tj-             H         O        ^O         O     '. 

oo          M      q     oo      t-  . 
•                  d      d          H      M      d      d    ; 

•                        H^ 

^^3?5>4,    2 

4    M     d 

;                 4     >,  4      *o      M*      «o      M*  M 

W?N)*5p°S     S 

d 

.4      *     i  ^  *! 

•cowwvi  « 

Tf          VO             -<fr 
VO            0           M 

M      o      d  . 

Tf                                     10               .             N             >0   tO 

w                      M         *        w        O  O 

•gat*  2 

CO                             M 

d             d 

tO                                00            M          00            M    f- 
VO                                   10           M          VO            M    O 

d                d      d      d      d  d 

•co*o>  «n   * 

;       •; 

o                oo      o      o     o  N 
vo                 10     o     10      q  o 
d                d      d      d      d  d 

jo  spixombsag    °° 

o      o      to 
IN      d     d 

IN                  o       I     ^     "o  •* 

M                                   H                                   O                           W            0     M 

•JBUa^BJ^ 

:    8    5- 

•       00        0 
«o 

I            q            *    ;    t*    *  ; 

^                        to          •         w 

pioy    oyuB^ix    « 

!      o      o 
«      o 
•      d      d 

'.            o>            »o     ;    o     o  o 

d                 d       •      M      M  M 

I 
z(*aSn         «* 

o      o      o 

>0          00             Tf 

\o'     *^     o* 

i          .  S     .    1    «,    o  : 

t*        0             00                   O         M     • 

t-           M            10 

10         00                   0           HI            «~-           •*  M 

1^.        O        O 

d      4         o    o      4    o  r; 

oo      «o      o 

>o     o         10      o     t-      o  o 

•(0ZH)  **»         ^ 

«0       O        0 
to         W         VO 

VO                         to      *O              %      t»       «*        2vO 

-BAV.  pauiquioQ 

M                       vN 

,0          U,                  „          U,          «.           JtJJ 

•(8oziv) 

O          M          1O 

o            o    S,      o    £    2    £8 

S      <?     "to 

S            M    2       J?    S     ?   ^^ 

•(ZQIg)    BO 

MOO 

t^.                        OO             iO^-OOO«0 
to                         vOt^              tOt»(MO>0 

"HIS  pautquioQ     M 

O       00         0 

00                             tOO                OOONtO-* 
Tt                        Mvo              tNvo-<J-^-rf 

Name  of  Company  and  Location. 

China  Clays. 

Kaolin  (washed),  Hockessin,  New- 
castle County,  Delaware  
China  clay,  Redruth,  Cornwall, 
England.*  
China  clay,  from  Huron,  Lawrence 
County,  Indiana.*  

c            ^  '  >!        ^  '   -fe'2    '*§   '*S 
w    t^    .W.2"S.2     K>O'o2  §,        ^-^5 

SILICATES. 


249 


•<t-        to        to        O                         vo         Ov 

O         O         O  to                        ^t 

o  •*     o> 

IO        vO           CO         O                               CO         t*» 

O         co        co  O                         OO 

tooo       10 

8    8    8    8            8    •& 

8    8    88            8 

O   Ov        O> 
0   Ov        O> 

vO         CO                                                 0.        Pi 
r^        O           .          .                       vo       00 

Ov    I                        to 

vO      .                               O\ 

o    !      o 

Ov     .          Ov 

O         M           •           •                          O         O 

M        '                                     O 

o    •      p» 

•*          M           N           0                             to            I 

0        co       r-    '                     r- 

t-\0         t- 

Ov       vo          M          co                           Ov 

PI       co      ov   .                   q 

Ov  O        to 

Pi 

*          P.      ,                               Ov 

5    ?.  •]              81 

'             •       *                                -^ 

:5     : 

o      d        •                         d 

•      EH     •                       0 

•  o 

:f5 

M    co     :  1  °           o 

O         00      '.                             vO 

0     Ov           HI 

CO          N                                                         10 

CO    M               t^ 

co       «         ;J                          d 

0      M      d    ;                  pJ 

PI  p,     PI 

00         vO             i         00                              Ov 

^  M       fo      o    '                 o 

CO     ;   10        00 

VO        vo           .         PI                          1-1 

vO         TJ-    .                        ^\ 

X)        .    t-             M 

oo;-*                  o 

o       o                       be 

to    ;  0        0 

PI         Ov       10      00                        O 
t         10         0         CO                              1A 

00        vO      '                          O 

8  ivo     : 

O         O         M         Ov                         O 

0  °:      s 

co     •   O 

M      \o       r^      vo                     r-     ^ 

P  O         HI        vo     i                          ^J- 

r^  M       00 

50        vo        vo                               00 

pi       p>       to      to                    O      £>••- 

J*5   -..  •*  : 

M     PI              Pi 

t^        00         00             I                             00             '. 

:                 :           v^      :                                      0 

MO1'        00 

VO          PI         vo                                          00 

.     .    «•  .          fe 

M  oo     •       00 

M            10           10              •                                    HI               ' 

PI              M                 °                                                        VO                 I 

ffi                        —  '.. 

:     i    a  :           o 

PI  M   ;     o 

O         Ov        O          0400                    co          • 

IO        VO          00         O                                 HI              • 

,0    pj    vo'   o            ti     : 

>.!>.>. 

£    £     ^ 

O         O         co  O 

o    •      o 

Ov     •         00 

vd    '.      t^. 

HI            10           to                                                   H               . 

1   1    "1             : 

00         vO           CO       f^T  Ov                       HI          f. 

o       M       -t     U  q               Ov      ov 
to      dv      4     ^  d              06      r^- 

O        r^        Ov  "">                        PI 

oo      o.     q  o                 oo 

t^-        to        co  0                          o> 

0000          PI 
«o  r-        co 
l^.  ro         <N 

t-  Ov       vo 

r-       t^        0         "  >o                 00        r- 

0        vo         0   Pi                          i^ 

8«->      o 

to        TJ-       Ov  t^                      00 

10       vo 

06        r-       t~-      ^Qo                   H         co 

o       Ov     oo  o                   M 

r^.  d       vo" 

00        00        vo          rj-                          00        00 

00        t-        O-PI                        r~ 

00  to        PI 

01^            •* 

r»       t/>       «        o                      MO 

Tj-            10            TJ-VO                                         Ov 

PI             M             M             M                                    CO           Tf 

CO         PI          «    Pi 

CO  PI           Pi 

CO           O             O             O                                     Ov         00 

O         PI         to        rf                         co        t^ 

vo        r-        PI  P«                         cv, 

00         0 
Ov  to        co 

c  '-.2  :.S  •  c"  •             +:»  '• 

O     '^3     '  cS     -0 

1  :°.  :s  ;|        §j  : 

co  :  g  :  g  :  ..             ^-o  : 

:  3  :  S  :"6           ^ 

•^       -4->       ••g 

*  c    *00    *ir                  -^ 

•     •  >.    '• 

'         '^H         " 

!   1*3   '. 

'.   '.x   '. 
•  o    . 

Pipe  Clay. 

,„    -  p    -£    •  o                      c'y    • 

•"  :•=  :o  :o>;           -5=°  : 
^I:S  ;d"      &  ^°r: 

*g:1:b  1.1*; 
itli3  ^f   s  "£  • 

^UfS       H4 

.  o    .  ^    .  r^                  o 

^ii  !l 

*.    -'C* 

•d  -^  >, 

iii  I 

B5JJI 

5S"^ 

ai* 

Mm 

5^   ^ 

C/2-McN    K 

5li 

^   ^    <i   ^              ow 

H-i^'cSctf           > 

o  rtO^^i  fl                5 
P^     ^     W                j§ 

***     K 

fll 


250  THE  NON-METALLIC  MINERALS. 

The  bibliography  of  clays  is  very  extensive,  and  but  a  few  refer- 
ences are  given  here.  The  reader  is  referred  particularly  to  Branner's 
Bibliography  of  Clays  and  the  Ceramic  Arts,1  and  to  the  papers  of 
Dr.  H.  Ries  in  the  reports  on  the  Mineral  Resources  of  the  United 
States,  published  annually  by  the  U.  S.  Geological  Survey. 

S.  W.  JOHNSON,  JOHN  M.  BLAKE.     On  Kaolinite  and  Pholerite. 

American  Journal  of  Science,  XLIII,  1867,  p.  351. 

J.  C.  SMOCK.     The  Fire  Clays  and  associated  Plastic  Clays,  Kaolins,  Feldspars,  and 
Fire  Sands  of  New  Jersey. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  VI,  1877,  p.  177. 
GEORGE  H.  COOK.     Report  on  the  Clay  Deposits  of  Woodbridge,  South  Amboy,  and 
other  places  in  New  Jersey. 

Geological  Survey  of  New  Jersey,  1878. 
RICHARD  C.  HILLS.     Kaolinite,  from  Red  Mountain,  Colorado. 

American  Journal  of  Science,  XXVII,  1884,  p.  472.     See  also  Bulletin  No.  20, 
U.  S.  Geological  Survey,  1885,  p.  97. 

J.  P.  LESLEY.     Some  general  considerations  respecting  the  origin  and  distribution  of 
the  Delaware  and  Chester  kaolin  deposits. 

Annual  Report  Geological  Survey  of  Pennsylvania,  1885,  p.  571. 
J.  H.  COLLINS.     On  the  Nature  and  Origin  of  Clays:  The  Composition  of  Kaolinite. 
Mineralogical  Magazine,  VII,  December,  1887,  p.  205. 
American  Journal  of  Science,  XLII,  1892,  p.  n. 
EDWARD  ORTON.     The  Clays  of  Ohio,  Their  Origin,  Composition,  and  Varieties. 

Report  of  the  Geological  Survey  of  Ohio,  VII,  1893,  pp.  45-68. 
EDWARD  ORTON,  JR.     The  Clay  Working  Industries  of  Ohio. 

Report  of  the  Geological  Survey  of  Ohio,  VII,  1893,  pp.  69-254. 
H.  O.  HOFMAN,  C.  D.  DEMOND.     Some  experiments  for  Determining  the  Refractori- 
ness of  Fire  Clays. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXIV,  1894,  p.  42. 
W.  MAYNARD  HUTCHINGS.     Notes  on  the  Composition  of  Clays,  Slates,  etc.,  and  on 
some  Points  in  their  Contact-Metamorphism. 
The  Geological  Magazine,  I,  1894,  p.  36. 

H.  JOCHUM.     The  Relation  between  Composition  and  Refractory  Characters  in  Fire 
Clays. 

Minutes  of  Proceedings  of  the  Institution  of  Civil  Engineers,  CXX,  1894-95, 

P-  431- 
HEINRICH  RIES.     Clay  Industries  of  New  York. 

Bulletin  No.  12  of  the  New  York  State  Museum,  III,  March,  1895,  pp.  100-262. 
JOHN  CASPER  BRANNER.     Bibliography  of  Clays  and  the  Ceramic  Arts. 

Bulletin  No.  143,  U.  S.  Geological  Survey,  1896. 

W.  S.  BLATCHLEY.     A  Preliminary  Report  on  the  Clays  and  Clay  Industries  of  the 
Coal  and  Coal-Bearing  Counties  of  Indiana. 

The  School  of  Mines  Quarterly,  XVIII,  1896,  p.  65. 
W.  MAYNARD  HUTCHINGS.     Clays,  Shales,  and  Slates. 

The  Geological  Magazine,  III,  1896,  p.  309. 

J  Bulletin  No.  143,  U.  S.  Geological  Survey,  1896. 


SILICATES.  251 

CHAS.  F.  MABERY,  OTIS  T.  FLOOZ.     Composition  of  American  Kaolins. 

Journal  of  the  American  Chemical  Society,  XVIII,  1896,  p.  909. 
Clay,  Bricks,  Pottery,  etc. 

Thirteenth  Report  of  the  California  State  Mineralogist,  1896,  p.  612. 
THOMAS  C.  HOPKINS.     Clays  and  Clay  Industries  of  Pennsylvania. 

Appendix  to  the  Annual  Report  of  the  Pennsylvania  State  College  for  1897. 
HEINRICH  RIES.     The  Clays  and  Clay- Working  Industry  of  Colorado. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXVII,  1897, 

P-  336- 
H.  A.  WHEELER.     Clay  Deposits. 

Missouri  Geological  Survey,  XL 
HEINRICH  RIES.     Physical  Tests  of  New  York  Shales. 

School  of  Mines  Quarterly,  XIX,  1898,  p.  192. 

The  Ultimate  and  the  Rational  Analysis  of  Clays  and  Their  Relative  Advan- 
tages. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXVIII,  1898, 
p.  160. 
G.  E.  LADD.     Preliminary  Reports  on  Clays  of  Georgia. 

Bulletin  No.  6A,  Geological  Survey  of  Georgia,  1898. 
HEINRICH  RIES.     Preliminary  Reports  on  Clays  of  Alabama. 

Bulletin  No.  6,  Geological  Survey  of  Alabama,  1900. 
• Clays  and  Shales  of  Michigan. 

Vol.  VIII,  Part  I,  Geological  Survey  of  Michigan,  1900. 
Clays  of  New  York. 

Bulletin  No.  35,  Vol.  VII,  New  York  State  Museum,  1900. 
E.  R.  BUCKLEY.     The  Clays  and  Clay  Industries  of  Wisconsin. 

Bulletin  No.  8,  Wisconsin  Geological  and  Natural  History  Survey,  1901. 
L.  DE  LAUNAY.     Observations  sur  les  Kaolins  de  Saint  Yrieux. 

Annales  des  Mines,  Vol.  Ill,  Part  I,  1903,  p.  105. 
EARLE  SLOAN.     A  Preliminary  Report  on  the  Clays  of  South  Carolina. 

South  Carolina  Geological  Survey,  Bulletin  No.  i,  Series  4,  1904. 
GERALD  FRANCIS  LAUGHLIN.     The  Clays  and  Clay  Industries  of  Connecticut. 

State  Geological  and  Natural  History  Survey,  Bulletin  No.  4,  1905. 
JAMES  H.  GARDNER  and  others.     Some  Kentucky  Clays,  including  Kaolinitic,  Plastic, 
and  Fire  Clays. 

Kentucky  Geological  Survey,  Bulletin  No.  6,  1905. 
A.  G.  LEONARD  and  others.     [Clays  of  North  Dakota.] 

State  Geological  Survey  of  North  Dakota,  Fourth  Biennial  Report,  1906. 
JOHN  T.  PORTER  and  others.     Investigations  relating  to  Clay  and  Clay  Products  by 
the  U.  S.  Geological  Survey  in  1906. 

U.  S.  Geological  Survey,  Bulletin  No.  315,  Contributions  to  Economic  Geology, 
1906,  pp.  268-355. 

H.  RIES.     Clays,  Occurrences,  Properties  and  Uses.     Wiley  &  Sons,  New  York,  1906. 
JOHN  C.  BRANNER.     The  Clays  of  Arkansas. 

U.  S.  Geological  Survey,  Bulletin  No.  351,  1908. 
HARRISON  EVERETT  ASHLEY.     The  Colloid  Matter  of  Clay  and  its  Measurement. 

U.  S.  Geological  Survey,  Bulletin  No.  388,  1909. 
OTTO  VEATCH.     Second  Report  on  the  Clay  Deposits  of  Georgia. 

Geological  Survey  of  Georgia,  Bulletin  No.  18,  1909. 


252 


THE  NON-METALLIC  MINERALS. 


1 6.  FULLERS'  EARTH. 

The  name  fullers'  earth  is  made  to  include  a  variety  of  clay-like 
materials  of  a  prevailing  greenish-white  or  gray,  olive  or  olive-green 
or  brownish  color,  soft,  and  with  a  greasy  feel.  When  placed 
in  water  such  fall  into  powder,  imparting  a  slight  murkiness  to 
the  liquid,  but  do  not  become  plastic  to  the  same  extent  as  the 
ordinary  clays. 

For  a  long  time  the  principal  source  of  fullers'  earth  was  Eng- 
land, but  an  increased  demand  has  resulted  in  the  discovery  of 
large  quantities  on  American  soil,  the  more  important  localities 
thus  far  developed  being  Bakersville,  California;  Gadsden  County, 
Florida,  and  Custer  County,  South  Dakota.  The  more  important 
foreign  sources  are  Bala,  in  North  Wales,  and  Buckingham  and 
Surrey,  in  England. 

The  celebrated  beds  at  Nutfield,  near  Redhill,  Surrey,  England, 
occur  in  Cretaceous  formations,  a  section  of  which  is  here  given.1 

Folkstone  beds,  gray  and  iron  shot  sand 15  ft. 

Buff  sandy  clay  with  greensand 15    " 

Soft  sandstone 4   " 


Sandgate 
beds 


Greenish  sandy  clay J    ' 

Sandstone 12    " 

Fullers'  earth.  .  8    " 


The  fullers'  earth  bed  sometimes  reaches  a  thickness  of  12  feet. 
The  upper  portion  is,  as  a  rule,  oxidized  to  a  brownish  color  by 
the  action  of  percolating  water,  the  lower  portion  being  blue.  In 
addition  to  the  analyses  given  on  p.  254  the  following  are  of  interest 
as  showing  the  relative  amounts  of  soluble  and  insoluble  matters.2 

BLUE  EARTH.     (Dried  at  100°  C.) 


Insoluble  residue 69-96%  = 

Fe203 2.48% 

AL03    3-46% 

CaO 5-87% 

MgO 141% 

P205 °-27% 

S03.  ., 0.05% 

NaCl 0.05% 

K20 0.74% 

H2O  (combined) 15-57% 

99-86% 


Insoluble  Residue. 
SiO, 


Fe20r 
CaO.  . 
MgO.. 


69.96% 


1  H.  B.  Woodward,  Geology  of  England  and  Wales,  p.  371. 

2  P.  G.  Sanford,  Geological  Magazine,  Vol.  VI,  1889,  pp.  456  and  526. 


FIG.  i. — Fuller's  Earth  Pit,  Quincy,  Florida. 
[After  H.  Ries:  Clays,  Their  Properties  and  Uses.] 


FIG.  2. — Phosphate  Pit,  Florida. 

[From  a  Photograph.] 

PLATE    XXIV. 


[Facing  page  252.] 


SILICATES.  253 

YELLOW  EARTH.      (Dried  at  100°  C.) 


Insoluble  residue 76.13%  = 

Fe203 2.41% 


A12O 


ff 


Insoluble  Residue. 

SiO.....    59.37% 
A1203....    10.05% 


Fe203.  ..      3.86% 

CaO 1.86% 

MgO...      1.04% 


CaO 4.31% 

MgO 1.05% 

P205 0.14% 

S03 0.07%                           76.18% 

NaCl 0.14% 

K20 0.84% 

Combined  waters 13.19% 

100.05% 

When  examined  with  a  microscope  this  material  is  found  to 
consist  of  extremely  irregular  corroded  particles  of  a  siliceous  min- 
eral which  in  its  least  altered  state  is  colorless,  but  which  in  nearly 
every  case  has  undergone  a  chloritic  or  talcose  alteration  whereby 
the  particles  are  converted  into  a  faintly  yellowish -green  product 
almost  wholly  without  action,  on  polarized  light.  These  are  of  all 
sizes  up  to  0.07  mm.  The  larger  portion  of  the  material  is  made 
up  of  particles  fairly  uniform  in  size  and  about  the  dimensions 
mentioned.  In  addition  to  these  are  minute  colorless  fragments 
down  to  o.o i  mm.  in  diameter,  and  even  smaller. 

The  minute  size  of  these  colorless  particles  renders  a  determina- 
tion of  their  mineral  nature  practically  impossible,  but  the  outline 
of  the  cleavage  flakes  is  suggestive  of  a  soda  lime  feldspar.  The 
high  percentage  of  silica  in  the  insoluble  residue  would  indicate 
the  presence  of  a  considerable  amount  of  free  quartz.  This,  how- 
ever, the  microscope  only  partially  substantiates,  very  few  of  the 
particles  showing  the  brilliant  polarization  colors  characteristic  of 
this  mineral.  (See  Plate  XXV,  Fig.  2.) 

The  Gadsden  County,  Florida,  earth  is  a  light-gray  material, 
often  blackened  by  organic  matter,  and  shows  under  the  micro- 
scope the  same  greenish,  faintly  doubly  refracting  particles,  as  does 
the  English,  intermixed  with  numerous  angular  particles  of  quartz. 
This  earth  is  quite  plastic  and  sticky  when  wet.  A  section  of 
the  beds  at  the  pits  of  the  Cheesebrough  Manufacturing  Com- 
pany, as  given  in  The  Mineral  Resources  for  1895-96,  is  as 
follows : 


254 


THE  NON-METALLIC  MINERALS. 


Soil 18  ins. 

Red  clay 3    ft. 

Blue  clay 3     " 

Fullers'  earth 5}  " 

Sandy  blue  earth. 3     " 

Fullers'  earth  (second  bed) Thickness  not  stated. 

The  following  table  *  as  compiled  by  Dr.  Ries  shows  the  variable 
character  of  the  earth  from  different  sources : 


b 

:o 

, 

% 

iS 

Ac 

Srt 

BS 

i-^ 

fa 

X~N 

*c3 

5 

C 

& 

'rt  rt 

U  ^-s 

JH  ^ 

^       /^v 

cfl  rt 

<D 

3 

« 

'5 

w 

a 

0^ 

Q'S) 

« 

^^? 

PI 

^3 

0 

1 

GO 

2 

o 

o^ 

U 

u,  o 

rt  W 

5^| 

^^s 

^1 

Con- 

g 

__rt 

E 

A 

Jd 

»^  ^* 

w  <«s 

+j  3  ^ 

r"  ^ 

stituents. 

§ 

r 

8 

u 

ti 

"C  c 

•£  ^> 

w  rt  . 

rt  °  te 

ife 

rt  3 

rt  C 

fl    • 

VH 

W  S* 

W  *t3 

w^ 

W  o 

"«fe^ 

IH  --C    O 

o 

W  rt 

a 

J"  ^ 

••sS 

"12^ 

"i?T3 

K 

•joCJ 

v*S  o 

^^? 

-g  8s8 

*c  ^ 

o 

• 

S-^ 

OJ  C 

D  C 

jj  S 

d>   JH 

*""  rt  "rt 

-  0  § 

dj  f~  ^ 

o3  o 

1 

£ 

S«s 

I 

I 

•3-0 

I 

fe^^ 

P-H 

i 

3^ 
fi 

SiO2.    . 

e  I  21 

C?  OO 

CO.  I? 

44.00 

4.J.  OO 

62  83 

67  4.6 

s8  72 

CQ    7O 

s8  ^o 

rA  60 

A1203  

12.25 

10.00 

10.66 

II.OO 

23.06 

IO-35 

/•^ 
10.08 

16.90 

2I.O7 

10.63 

10.99 

Fe,O,  . 

2.O7 

Q.7C 

7   T  C 

IO  OO 

2.OO 

2.4.^ 

2.4-O 

400 

688 

6  72 

6  61 

CaO  

2.13 

•50 

•25 

5.00 

4.08 

2-43 

3-14 

4.06 

4.40 

I.7I 

6.00 

MgO  

A    &O 

2.OO 

2.OO 

4.OQ 

2.i;6 

20 

31  c 

•y  oo 

H0O.  . 

27.80 

24.00 

-  g 

24..CK 

^.72 

5.61 

••3V 

8.10 

0.60 

0  O^ 

IO  ^O 

f.. 

5.00 

O.20 

:1 

vr    A 

V 

2.  II 

K2O  

O.74 

j 

Moisture.  . 

6.41 

6.28 

2.7O 

7-QO 

o.erc; 

7  4.5 

Total.... 

100.44 

98.50 

100.06 

77.00 

IOO.O9 

96.25 

99-15 

98.75 

100.85 

99.11 

98-95 

(a)  Pogg.  Ann.,  LXXVII,  1849?  p.  591.  (/)  P.  Fireman,  analyst. 

(6)  Klaproth.  Beitr.,  Vol.  IV.  1807,  p.  338.         (g)  E.  J.  Riederer,  analyst. 

(c)  Dana,  System  of  Min.,  1893,  p.  695.  (fc)  Standard  Oil  Company's  property,  E.  J. 

(d)  Geikie,  1893,  p.  133.  Riederer,  analyst. 

(e)  Penny  Encyclopedia,  XI,  Dr.  Thompson,  (t)  Howell  property,  E.  J.  Riederer.  analyst. 

analyst.  (/)  Morgan  property,  E.  J.  Riederer,  analyst. 

Uses. — The  material  was  formerly  used  almost  wholly  by  fullers 
for  removing  the  grease  from  cloths.  It  is  now  largely  used  in 
deodorizing  and  clarifying  fats,  oils,  and  greases.  The  manufacturers 
of  lard  and  cottolene  are  large  consumers.  Some  2,000  to  3,000  tons 
are  annually  imported  and  25,000  to  30,000  tons  produced  in  the 
United  States.  The  value  is  about  $9.00  per  ton. 


1  Seventeenth  Annual  Report,  U.  S.  Geological  Survey,  Part  III,  1895-96,  p.  880 


x* 


,^ 
w    -  f  i*      * 

-^ 


FIG.  2. 

PLATE  XXV. 

FlG.  i,  Clay,  Albany,  Wyoming,  and  FIG.  2,  Fuller's  Earth,  as  Seen  under  the  Micro- 
scope. 
[U.  S.  National  Museum.] 

[Facing  page  254.] 


N1OBATES,   TANTALATES,    AND    TUNGSTATES. 


255 


VII.  NIOBATES,  TANTALATES,  AND  TUNGSTATES. 

I.    COLUMBITE   AND   TANTALITE. 

These  minerals  are  columbates  and  tantalates  of  iron  and  man- 
ganese, columbite  representing  the  nearly  pure  columbate  and 
tantalite  the  nearly  pure  tantalate.  Both  are  likely  to  carry  varying 
quantities  of  iron  and  manganese.  The  analyses  given  below  will 
serve  to  show  the  varying  composition,  No.  I  being  columbite  from 
Greenland,  No.  II  from  Haddam,  Connecticut,  and  Nos.  Ill  and 
IV  from  the  Black  Hills  of  South  Dakota: 


Constituents. 

I. 

II. 

III. 

IV. 

Columbium  pentoxide  
Ta.nta.lium  pentoxide. 

77-97 

51-53 
28  cc 

54-09 
18  20 

29.78 

C-7    28 

Iron  protoxide. 

17  3  3 

I  3   ">d. 

II   21 

JO"'0 

6  ii 

Manganese  protoxide.  — 

3.28 

4-55 

7.07 

10.40 

With  traces  of  tin,  wolfram,  lime,  magnesia,  etc. 

The  minerals  are  of  an  iron-black,  grayish,  or  brownish  color, 
opaque,  often  with  a  bluish  iridescence,  dark- red  to  black  streak, 
specific  gravity  varying  from  5.3  to  7.3  and  hardness  of  6.  In- 
soluble in  acids. 

Occurrence. — Columbite  occurs  in  granitic  and  feldspathic  dikes 
in  the  form  of  crystals,  crystalline  granules,  and  cleavable  masses. 
In  the  United  States  it  has  been  found  in  greater  or  less  abundance 
in  nearly  all  the  States  bordering  along  the  Appalachian  Mountain 
system,  in  the  Black  Hills  of  South  Dakota,  and  also  in  California 
and  Colorado.  It  has  also  been  found  in  Italy,  Bavaria,  Finland, 
Greenland,  and  western  South  America.  Tantalite  occurs  under 
similar  conditions. 

Uses. — The  material  is  used  only  in  the  preparation  of  salts  of 
columbium  and  tantalium,  and  is  in  but  little  demand,  except  for 
mineralogical  specimens. 

2.    YTTROTANTALITE. 

This  name  is  given  to  a  mineral  closely  related  to  samarskite  (see 
next  page),  but  carrying  smaller  percentages  of  uranium  and  lacking 


256 


THE  NON-METALLIC  MINERALS. 


in  didymium  and  lanthanum.  It  is  essentially  a  tantalate  of  yttrium 
with  small  amounts  of  other  of  the  rarer  earths.  In  appearance 
it  is  distinguished  from  samarskite  only  with  difficulty.  Pyrochlore, 
fergusonite,  aeschynite,  euxenite,  etc.,  are  closely  related  compounds, 
the  commercial  uses  of  which  have  not  yet  been  demonstrated. 

3.    SAMARSKITE. 

Composition  as  given  below.  When  crystallized,  in  the  form  of 
rectangular  prisms,  but  occurring  more  commonly  massive  and  in 
flattened  granules.  Cleavage,  imperfect;  fracture,  conchoidal; 
brittle.  Hardness,  5  to  6;  specific  gravity,  5.6  to  5.8.  Luster, 
vitreous  to  resinous.  Color,  velvet-black.  Analyses  of  North  Caro- 
lina materials  yielded : 


Constituents. 

I. 

II. 

III. 

IV. 

Columbic  oxide 

) 

I     77  ?O 

Tantalic  oxide 

f   54-Si 

54-96 

5S'*3 

(    18  60 

Tungstic  and  stannic  oxides 

o  1  6 

O  31 

o  08 

Uranic  oxide 

17  O3 

O  01 

10  06 

12  46 

Ferrous  oxide 

14  O7 

14  O2 

1  1  74 

10  90 

iManganous  oxide. 

O.QI 

I   C  2 

O  7  J 

Cerous  oxide,  etc.       .        .  .      .... 

•7  Qtr 

C.i7 

4.24 

4  2S 

Yttria.               

II.  II 

0-i  / 
12.84 

14.40 

14.4  <( 

M^agnesia.  .       ................... 

Trace. 

Lime      .    .    .    ................... 

O.^2 

o.zz 

Loss  by  ignition  

O.24 

0.66 

0.72 

1.  12 

IOI.2I 

100.40 

99.12 

100.36 

Localities  and  mode  oj  occurrence. — The  only  localities  of  im- 
portance in  the  United  States  are  the  Wiseman  Mica  Mine  and 
Grassy  Creek  Mine,  in  Mitchell  County,  North  Carolina.  At  the 
Wiseman  Mine  large  masses,  one  weighing  upwards  of  20  pounds, 
were  found  some  years  ago.  The  analyses  quoted  above  were 
made  from  material  from  this  mine.1  The  mineral  has  also  been 
found  in  Rutherford  and  McDowell  counties. 

Uses. — See  under  Monazite,  p.  298. 


1  See  Minerals  of  North   Carolina,   Bulletin   No.  74,   U.  S.   Geological   Survey, 
1891. 


NIOBATES,  TANTALATES,  AND  TUNGSTATES. 


257 


4.    WOLFRAMITE,    HUBNERITE,    AND   FERBERITE. 

Composition. — Wolframite  is  a  tungstate  of  manganese,  and  iron. 
The  proportions  of  the  iron  and  manganese  are  quite  variable,  the 
tungsten  remaining  nearly  constant.  The  name  hiibnerite  is  given 
to  the  variety  containing  very  little  iron,  but  consisting  essentially 
of  tungsten  and  manganese.  Ferberite  is  the  theoretically  pure 
ferrous  tungstate.  The  following  table  shows  the  range  in  com- 
position : 


Locality. 

WOs 

FeO. 

MnO. 

CaO. 

MgO. 

Wolframite: 
Adun-Chalon            

7C    e  r 

21.71 

2-37 

0.26 

O.CI 

^Monroe   Connecticut 

7s    47 

9r  'i 

14    26 

Hiibnerite: 
Bonita   New  Mexico   .... 

76.  T,T, 

3.82 

19.72 

o.  13 

Trace. 

Nye  County,  Nevada  
Ferberite: 
Colorado 

74-88 

74.    I  "? 

° 
0.56 

23     Is1 

23-87 

o  <6 

0.14 
I   28 

0.08 

These  are  all  dark  reddish  brown  to  black  in  color,  with  a 
resinous  luster;  a  hardness  of  about  5,  a  specific  gravity  of  7.55, 
and  a  pronounced  tendency  to  cleave  with  flat,  even  surfaces.  The 
great  weight,  color,  and  cleavage  tendencies  are  strongly  marked 
characteristics,  and  the  minerals  once  identified  are  easily  recognized. 

Occurrence. — The  tungstates  are  found,  as  a  rule,  in  veins,  often 
associated  with  tin  ores,  and  also  with  quartz,  pyrite,  galena,  and 
sphalerite.  The  principal  known  localities  in  the  United  States 
are  Boulder  and  Gilpin  counties,  Colorado;  Monroe  and  Trumbull 
counties,  Connecticut;  Blue  Hill  Bay,  Maine;  Rockbridge  County, 
Virginia;  Mecklenburg  County,  North  Carolina;  The  Black  Hills, 
South  Dakota;  Stevens  County,  Washington;  Russellville,  Arizona; 
Nye,  Lanier,  and  Osceola  counties,  Nevada;  Lincoln  County,  New 
Mexico;  Falls  County,  Texas.  Wolframite  has  been  also  reported 
from  Oregon,  Montana,  and  Idaho.  The  principal  foreign  localities 
are  the  tin  regions  of  Cornwall,  England;  Bohemia,  Saxony,  and 
Autsralia.  It  is  also  found  in  Peru,  Bolivia,  and  the  Argentine  Republic. 

In  the  Black  Hills  region  of  South  Dakota  wolframite,  ac- 
cording to  J.  D.  Irving,1  occurs  in  connection  with  a  crystalline 

1  Transactions  of  the  American  Institute  of  Mining  Engineers,  XXXI,  1901, 
p.  682. 


258  THE  NON-METALLIC  MINERALS. 

dolomite  lying  between  shales  above  and  quartzite  and  auriferous 
gravels  below.  The  dolomite  is  often  highly  siliceous,  and  passes 
at  times  through  the  intermediate  stage  of  a  dolomitic  sand  rock 
into  quartzite,  the  silicification  in  such  cases  seeming  to  have 
been  contemporaneous  with  the  formation  of  the  ore  body.  The 
wolframite  itself  occurs  in  flat,  horizontal  but  rather  irregular  masses 
of  all  thicknesses  up  to  2  feet.  Such  frequently  cover  considerable 
areas,  but  are  so  extremely  irregular  that  it  is  difficult  to  form  exact 
estimates  of  their  extent. 

The  ore  bodies  are  intimately  associated  with  the  flat  masses 
or  chutes  of  refractory  siliceous  gold  ore,  which  has  been  so  ex- 
tensively developed  of  late  years  in  this  region,  and  which  consists 
of  an  extremely  hard,  brittle  rock,  composed  chiefly  of  secondary 
silica,  carrying  pyrite,  fluorite,  barite,  and  occasionally  gypsum. 
In  the  areas  where  the  wolframite  is  found  the  siliceous  ore  is  always 
oxidized  and  is  usually  coarse  in  texture.  The  ore  is  generally 
banded,  the  banding  being  continuous  with  the  bedding  planes  of 
the  adjoining  strata,  and  the  chutes  occur  along  lines  of  fracture 
termed  verticals,  on  either  side  of  which  the  dolomite  has  been 
replaced  for  a  distance  varying  from  a  fraction  of  an  inch  up  to  12 
feet. 

Investigation  of  the  ore  bodies  of  this  type  shows  that  they  are 
replacements  of  the  dolomitic  beds  by  silica,  pyrite,  and  other  min- 
erals, the  mineralizing  waters  having  gained  access  to  the  soluble 
beds  through  the  fractures  above  mentioned.  At  times  the  wol- 
framite forms  a  rim  around  the  outer  edge  of  the  siliceous  ore  chutes, 
often  extending  inward  and  upward  so  as  to  form  a  thin  capping 
for  the  ore.  It  thus  appears  as  a  sort  of  envelope  to  the  siliceous 
ore  mass  which  it  incloses  on  all  except  the  lower  sides.  Margins 
of  this  kind  are  often  2  to  2^  feet  thick,  though  the  capping  portion 
is  usually  thinner.  At  other  times  the  wolframite  occurs  in  ir- 
regular masses  scattered  through  the  siliceous  ore  or  in  stringers 
and  thin  contorted  layers  in  the  partially  silicified  dolomite.  In 
general  the  ore  is  separated  from  the  non-mineralized  rock  by  a 
fairly  sharp  line  of  demarkation,  but  in  many  instances  it  grades- 
off  so  that  the  ore  becomes  leaner  and  passes,  by  almost  impercep- 
tible gradations,  into  the  country  rock. 


NIO BATES,    TANTALATES,  AND    TUNGSTATES. 


259 


As  taken  from  the  mines  the  wolframite  is  a  dense  black  massive 
rock,  of  fine  granular  texture  and,  of  course,  great  weight,  closely 
resembling  a  fine-grained  magnetite,  but  having  a  greater  specific 
gravity  and  slightly  brownish  streak.  An  analysis  of  this  ore,  as 
made  by  W.  F.  Hillebrand  of  the  U.  S.  Geological  Survey,  is  given 
below  and  also  a  calculation  made  from  these  analyses  to  show 
the  proportions  of  the  principal  minerals  contained  therein. 

As  to  the  source  of  the  ore  in  these  deposits  there  is  some  ques- 
tion, but  it  is  thought  most  probable  by  Irving  that  circulating 
waters  permeating  the  Algonkian  rocks  below  brought  the  material 
to  its  present  position,  where  it  was  deposited  through  a  process  of 
metasomatic  interchange;  this  being  true,  this  particular  deposit 
would  belong  to  the  category  of  what  are  known  as'  secondary. 
Wolframite,  it  should  be  stated,  is  also  found  at  the  Etta  Tin  Mines 
and  at  Nigger  Hill  in  the  southern  portion  of  the  Black  Hills,  but 
under  totally  different  conditions,  being  here  a  constituent  of  the 
pegmatite,  and  hence  a  primary  mineral. 

ANALYSES    OF    BLACK   HILLS    WOLFRAMITE    ORE. 


Constituents. 

I. 

II. 

SiO,.  . 

Per  Cent. 
12.87 

Per  Cent. 
0.60 

WO,  . 

61.50 

y 
61.70 

Fe,O, 

7.8=5 

12.67* 

Feb.  

0.18 

ALO5.  , 

O.^2 

MnO  

8.21 

7.21 

CaO  

O.O7 

C.2Q 

SrO.    ...           

BaO                      

K2O  +  Na2OLi2O  

0.08 

O.2of 

HlO.  . 

0.87± 

As,(X  . 

P,0v 

VO 

Trace. 

o.ioS 

S  or  SO3  

Trace. 

99.64 

Assays  of  I. — Gold,  0.05  oz.  per  ton;    silver,  0.25  oz.  per  ton. 
Extremely  minute  traces  of  Mg,  Zn,  Cu,  Sb,  and  Sn  were  also  found. 
*  Determined  as  Fe2O3,  includes  FeO. 
tUp  to  io5°C. 
I  Above  105°  C. 
§  Approximate. 


260 


THE  NON-METALLIC  MINERALS. 


PROPORTIONS    OF    PRINCIPAL    MINERALS. 


Constituents 

I. 

II 

Wolframite  (FeMn)O.WO,  
Quartz,  SiO2.                        .    .    . 

75.60 
12.154 

5I-58 

0.60 

Scheelite,  CaO.WO    

4-77 

27.68 

Barite,  BaO.SO3     

0.06 

Ferric  oxide  FeO 

1  8s 

Water,  H^O  

O.2O 

I.2S 

Residual  clay  (kaolin) 

1.34 

According  to  State  Commissioner  of  Mines  Harry  A.  Lee, 
wolfram  occurs  in  several  counties  in  Colorado.  In  Boulder  and 
Gilpin  counties  it  has  been  found  in  a  complex  of  granite,  gneiss, 
and  schist,  where  it  occurs  in  small  pockets  or  streaks  disseminated 
through  fissure  veins. 

R.  D.  George  states  1  that  the  ore  is  largely  in  the  form  of 
ferberite,  and  the  majority  of  the  veins  are  in  granite,  though  a  number 
of  good  producing  mines  are  close  to  the  contact  between  the  granite 
and  gneiss,  and  in  some  instances  in  the  gneiss  itself.  The  veins, 
however,  seemingly,  decrease  in  productiveness  or  become  quite 
barren  in  the  more  schistose  varieties  of  the  rock.  Throughout 
the  various  areas  the  veins  have  no  constant  trend,  the  angle  of 
dip  is  generally  steep,  often  vertical,  and  rarely  falling  below  45°. 
The  conditions  of  vein  formation  and  filling,  as  outlined,  are  as 
follows : 

(1)  A  period  of  earth  movements  in  which  fissures  were  formed, 
some  of  which  follow  the  pegmatite  and  granite  dikes,  while  others 
cut  the  country  rock.     At  the  close  of  the  movements  these  fissures 
were  left  partially  filled  by  loose  masses  of  angular  rock  fragments. 

(2)  Silica-bearing  waters,  probably  at  high  temperatures,  then 
circulated  through  the  rock  fragments  in  the  fissures,  and  by  a 
process  of  replacement  feldspars  and  biotite  in  the  rock  fragments 
were  slowly  dissolved  out  and  silica  in  the  form  of  chalcedony-like 
quartz   or   hornstone   deposited   in   their   place.     Locally   a   small 
deposition  of  ferberite  accompanied  this  replacement. 

(3)  This  was  followed  by  a  second  period  of  earth  movements 


1  First  Report  Colorado  Geological  Survey,  1908,  p.  60. 


NIOBATES,  TANTALATES,  AND  TUNGSTATES. 


261 


in  which  the  vein  breccia,  and  in  places  the  country  rock  itself  was 
crushed  and  mingled  into  a  new  mass  of  fragments.  This  movement 
was  accompanied  by  a  considerable  vertical  displacement  and  drag- 
ging along  the  walls  of  the  veins. 

(4)  This  period  was  followed  by  the  most  important  deposition 
of  tungsten.     The  heated  waters,  loaded  with  tungsten  salt,  rose 
toward  the  surface  and  deposited  the  ferberite  in  the  interstices  of 
the  rock  fragments.     In  places  more  or  less  silica  was  deposited 
with  the  ferberite. 

(5)  Then  followed  a  third  movement  which  crushed  the  vein 
filling  and  added  more  of  the  dike  rock  or  country  rock  to  the  frag- 
mental  mass.     This   was   followed   by    (6)    a   second   considerable 
deposition  of  hornstone  silica,  and  this  in  turn  by  (7)  a  second  period 
of  tungsten  deposition.     Following  this  there  were  (8)  contempora- 
neous depositions  of  silica  and  tungsten  ore  and  (9)  local  solutions 
of  the  tungsten  and  deposition  of  silica,  possibly  producing  a  sec- 
ondary enrichment. 

Formed  at  these  various  periods  there  is  naturally  considerable 
diversity  in  the  ores.  Professor  George  has  grouped  them  in  three 
rather  well-defined  forms  which  frequently  grade  into  one  another. 
These  are  (i)  well-crystallized  crusts  and  layers  covering  the  sur- 
face of  the  rock  fragments  and  cementing  them  into  a  breccia; 
(2)  massive,  granular  ore  showing  few  or  no  crystal  faces  and  oc- 
curring as  more  dense  seams  and  masses  in  the  wider  and  less  brec- 
ciated  portions  of  the  veins,  and  (3)  a  highly  siliceous  ore  in  which 
the  berberite  is  in  fine  grains,  sometimes  showing  crystal  forms,  and 
scattered  throughout  hornstone  or  cryptocrystalline  quartz. 

The  following  analyses  of  material  from  the  Nederland-Beaver 
Creek  area  of  Colorado,  as  given  by  George,  are  selected  as  showing 
the  average  composition.  The  CaO  is  regarded  as  belonging  to 
admixed  scheelite,  while  the  silica,  alumina,  and  magnesia  are 
present  as  impurities  and  non-essential: 


Localities. 

WO3. 

FeO. 

MnO. 

CaO. 

SiO2. 

AkOs. 

MgO. 

Clyde  Mine  
Lost   Chance 
Mine               .  . 

61.15 

62   20 

J9-33 

IO    QO 

Q-51 
o  60 

0.38 
O    7Q 

16.10 
14  68 

2.42 
I    34. 

°-39 

Manchester  Lake 

74    13 

2T.     1C 

o  c6 

I    28 

o  76 

o  46 

262  THE  NON-METALLIC  MINERALS. 

In  Osceola  County,  Nevada,  tungsten  in  the  form  of  hiibnerite 
occurs  in  veins  varying  from  6  to  36  inches  in  width,  and  having 
a  strike  north  70°  east  and  a  dip  of  65°  northwest.  The  veins  are 
in  granite  with  a  well-defined  selvage  and  carry  quartz  as  the  prin- 
cipal gangue. 

The  hiibnerite  is  found  in  crystals  and  masses  with  very  pro- 
nounced cleavage  planes  from  2  to  4  inches  in  length  and  i  to  3 
inches  in  width.  It  also  occurs  in  fine  grains  and  irregular  bodies, 
the  quartz  and  hiibnerite  having  apparently  been  deposited  con- 
temporaneously. In  a  few  instances  scheelite  has  been  found  as- 
sociated with  the  hiibnerite.  A  little  pyrite  and  fluorite  are  also 
occasionally  met  with.  The  ore  is  stated  to  have  averaged  from  65 
to  70  per  cent  of  WOs.1 

In  Arizona,  tungsten  ore,  also  in  the  form  of  hiibnerite,  occurs, 
according  to  W.  P.  Blake,  in  the  granite  hills  of  the  Dragoon  Moun- 
tains, about  6  miles  north  of  Dragoon  Summit  Station  on  the 
Southern  Pacific  Railway  in  Cochise  County. 

The  veins  here  are  nearly  vertical  and  generally  traverse  the 
granite  gneiss  in  the  direction  of  the  rude  structural  bedding  planes. 
They  are  from  a  few  inches  to  2  or  3  feet  in  width.  The  gangue 
material  is  quartz,  throughout  which  the  hiibnerite  occurs,  some- 
what irregularly  disseminated,  sometimes  in  patches  or  bunches 
centrally  disposed  with  quartz  on  either  side,  and  sometimes  dis- 
seminated from  side  to  side  or  in  layers  or  bunches  in  close  contact 
with  the  continuous  walls.  The  hiibnerite  itself  is  in  the  form  of 
large  tubular  blocks  or  thick  plates,  often  with  a  somewhat  radial 
arrangement,  penetrating  the  solid  gangue  of  white  quartz.  Masses 
of  all  sizes  up  to  500  pounds  in  weight  have  been  reported.  The 
color  of  the  mineral  is  light  brownish  red,  thin  films  or  plates  seen 
by  transmitted  light  being  of  a  ruby-red  color.-  Aside  from  quartz, 
which  forms  the  prevailing  gangue  mineral,  the  presence  of  a  little 
fluorspar  and  mica  has  been  noted. 

A.  M.  Finlayson  describes  2  tungsten  ores,  both  wolframite  and 

1  Fred.  D.  Smith,  Engineering  and  Mining  Journal,  March  i,  1902,  p.  304;    F. 
B.  Weeks,  2ist  Annual  Report  of  the  U.  S.  Geological  Survey,  1899-1900,  Part  VI, 

P-  3*9- 

2  Geological  Magazine,  January,  1910,  p.  20. 


NIOBATES,  TANTALATES,  AND  TUNGSTATES.  263 

scheelite,  occurring  in  small  veins  in  a  post  Silurian  "greisen"  in 
Carrock  Fell.  This  greisen  is  regarded  as  an  acid  modification  of 
the  Skiddaw  granite,  the  feldspar  of  the  normal  rock  having  almost 
wholly  disappeared,  and  a  white  mica  (gilbertite)  replacing  the  biotite, 
leaving  a  quartz  muscovite  aggregate  comparable  with  the  greisen 
of  the  Saxon  mines  and  having  some  points  in  common  with  the 
beresite  of  the  Russian  Urals  and  the  alaskite  of  J.  E.  Spurr.  The 
veins  consist  essentially  of  the  quartz  and  white  mica  mentioned 
with  a  pale  bluish-green  apatite.  There  is  a  complete  absence  of 
tourmaline,  fluorite  or  other  minerals  indicative  of  pneumotolitic 
action.  The  wolframite,  with  a  less  amount  of  scheelite,  is  dis- 
seminated irregularly  in  bunches  through  the  vein.  Some  arseno- 
pyrite  is  present  and  also  molybdenite. 
Uses. — See  under  Scheelite,  below. 

5.    SCHEELITE. 

This  is  a  calcium  tungstate,  consisting  when  pure  of  some  80.6 
per  cent  tungsten  trioxide  (WO 3)  and  19.4  per  cent  lime;  usually, 
however,  carrying  from  i  to  8  per  cent  of  molybdic  oxide  (MoO3). 
The  mineral  is  white  and  translucent,  sometimes  yellow  and  brownish 
in  color,  with  a  hardness  of  4.5-5,  gravity  6,  and  a  tendency  to 
cleave  into  octahedral  forms. 

Scheelite  is  much  less  common  in  its  occurrence  than  wolfram 
and  few  localities  of  any  apparent  commercial  importance  have 
thus  far  been  reported. 

A  deposit  that  at  one  time  seemed  promising  was  discovered 
some  years  ago  near  Long  Hill  Station  on  the  Housatonic  Railroad 
in  Trumbull  Parish,  Fairfield  County,  about  8  miles  from  the  city 
of  Bridgeport.  The  country  rock  is  a  metamorphic  amphibolic 
gneiss  of  a  dark,  blackish  color,  overlying  a  crystalline  limestone, 
and  this  in  turn  overlying  a  second  hornblendic  gneiss,  the  main 
mass  of  the  ore  being  segregated  along  the  line  of  contact  between 
the  limestone  and  the  hornblendic  gneiss,  the  latter  being  considered 
as  an  altered  igneous  rock  and  the  deposit  as  a  whole,  therefore,  a 
contact  deposit. 

In  the  main  opening  the  fresh  contact  rock  between  the  gneiss 


264  THE  NON-METALLIC  MINERALS. 

and  the  limestone  is  a  massive  quartz-zoisite-epidote-hornblende 
rock,  throughout  which  the  scheelite  is  irregularly  disseminated 
and  often  scattered  in  crystalline  masses  which  are  sometimes  as 
large  as  one's  fist.  Associated  with  the  scheelite  is  more  or  less 
pyrite,  and  numerous  crystals  of  wolframite  which  are,  however, 
in  all  cases  pseudomorphous. 

A  considerable  amount  of  capital  has  been  expended  in  prospect- 
ing and  in  the  erection  of  works  for  concentrating,  but,  so  far  as 
the  present  writer  has  information,  a  comparatively  small  amount 
of  pure  scheelite  has  thus  far  been  produced. 

Scheelite  has  been  found  in  some  quantity  in  gold-bearing  veins 
of  the  Minnehaha  mine  in  Kern  County,  California.  Two  "shoots'* 
of  the  ore  are  stated  to  occur  in  the  veins,  the  full  width  of  which 
is  from  18  to  20  inches.  The  hanging  wall  is  of  mica  schist  and  the 
footwall  of  limestone.1  Scheelite  is  also  known  to  occur  in  quartz 
veins  cutting  diorite  at  Atolia  in  San  Bernardino  County,  this  same 
State. 

Recent  reports  from  the  Canadian  Department  of  Mines2, indi- 
cate that  the  mineral  is  by  no  means  of  rare  occurrence  in  Nova 
Scotia,  British  Columbia,  and  other  parts  of  the  dominion.  It  is 
found  in  small,  disconnected,  lenticular  masses,  sometimes  forming 
a  third  or  fourth  of  the  filling  matter  in  gold-bearing  quartz  veins 
in  Halifax  County,  Nova  Scotia.  The  veins  are  in  slate,  of  all 
widths  up  to  22  inches,  approximately  parallel,  and  all  in  a 
belt  not  more  than  100  yards  in  width  following  the  strike  of 
the  slate,  which  is  here  east  and  west,  with  a  dip  of  80°  toward 
the  north.  Arsenopyrite  is  a  common  associate.  In  the  Barker- 
ville  district  of  British  Columbia  scheelite  occurs  associated  with 
iron  pyrites  and  galena  in  small  quartz  veins  and  vugs  in  mica 
schist. 

Uses. — Tungsten  is  used  mainly  in  the  manufacture  of  the 
so-called  self-hardening  steel,  the  material  being  introduced  either 
as  a  ferro-tungsten  or  as  the  powdered  mineral.  This  tungsten 
steel  is  said  to  be  particularly  adaptable  to  the  manufacture  of 


1  The  Mining  World,  Mar.  31,  1906,  p.  414. 

2  Report  on  Tungsten  Ores  of  Canada,  by  T.  L.  Walker,  1909. 


NIOBATES,  TANTALATES,  AND  TUNGSTATES.  265 

cutting  tools,  which  can  be  used  even  when  heated  to  temperatures 
that  would  destroy  the  temper  of  the  ordinary  carbon  steel.  Its 
consideration  in  this  connection  belongs  properly  to  works  on 
merallurgy.  It  is  also  used  in  the  preparation  of  tungstic  acid  and 
sodium  tungstates,  and  attempts  have  been  made  to  utilize  it  in 
porcelain  glazes,  though  thus  far  without  much  success. 

The  production  of  tungsten  ore  of  all  kinds  in  the  United  States 
during  1908  amounted  to  some  497  short  tons  of  concentrates, 
valued  at  $126,238.  The  price  of  the  tungsten  metal  in  IQOI  varied 
from  58  to  64  cents  per  pound,  of  the  ferro-tungsten  from  27  to  31 
cents  per  pound.  The  price  of  the  ore  during  1906-08  ranged 
from  $254  to  $487  per  ton,  the  ores,  as  a  rule,  carrying  from  60 
to  75  per  cent  of  WO.1  Prices  are  based  upon  the  per  cent  of 
tungstic  oxide,  the  concentrates  being  sold  by  the  "unit"  of  i  per 
cent,  or  20  pounds  per  short  ton. 

BIBLIOGRAPHY. 

J.  PHILLIP.     Tungsten  Bronzes. 

Journal  of  the  Society  of  Chemical  Industry,  I,  1882,  p.  152. 
The  Use  of  Wolfram  or  Tungsten. 

Iron  Age,  XXXIX,  1887,  p.  33. 
T.  A.  RICKARD.     Tungsten. 

Engineering  and  Mining  Journal,  LIII,  1892,  p.  448. 
Wolfram  Ore. 

Iron  Age,  XL,  1892,  p.  229. 
ADOLF  GURLT.     On  a  Remarkable  Deposit  of  Wolfram  Ore  in  the  United  States. 

Transactions  of  the  American  Institute  of  Mining  Engineers,    XXII,    1893, 
p.  236. 
HENRI  MOISSAN.     Researches  on  Tungsten. 

Minutes  of  the  Proceedings  of  the  Institution  of  Civil  Engineers,  CXXVI, 
1895-96,  p.  481. 
R.  HELMHACKER.     Wolfram  Ore. 

Engineering  and  Mining  Journal,  LXII,  1896,  p.  153. 
Prof.  BODENBENDER.     Wolfram  in  the  Sierra  de  Cordoba,  Argentine  Republic. 

Transactions  of  the  North  of  England  Institute  of  Mining  and  Mechanical 
Engineers,  XLV,  Pt.  3,  March,  1896,  p.  59. 
WM.  P.  BLAKE.     Hubnerite  in  Arizona. 

Transactions  of  the  America   Institute  of  Mining   Engineers,  XXVIII,  1898, 
P-  543- 

1  These  figures  are  taken  from  the  Mineral  Industry  for  1901. 


266  THE  NON-METALLIC  MINERALS. 

F.  B.  WEEKS.     An  Occurrence  of  Tungsten  Ore  in  Eastern  Nevada. 

2ist  Annual  Report  of  the  U.  S.  Geological  Survey,  1899-1900,  Pt.  VI. 
FRED  D.  SMITH.     The  Osceola,  Nevada,  Tungsten  Deposits. 

Engineering  and  Mining  Journal,  LXXIII,  March,  1902,  pp.  304,  305. 
J.  D.  IRVING.     Some  Recently  Exploited  Deposits  of  Wolframite  in  the  Black  Hills 
of  South  Dakota. 

Transactions  of  the  American  Institute  of  Mining  Engineers,   XXXI,   1902, 
pp.  683-685. 
W.  H.  HOBBS.     The  Old  Tungsten  Mine  at  Trumbull,  Connecticut. 

22d  Annual  Report  of  the  U.  S.  Geological  Survey,  1900-01.     Part  II,  p.  13. 
This  paper  gives  in  addition  to  description  of  occurrence,  matter  relative  to 
method  of  mining  and  concentration. 
R.  S.  BAUERSTOCK.     A  California  Scheelite  Deposit. 

The  Mining  World,  November  31,  1906;  gives  also  description  of  method  of 
concentration. 

R.  D.  GEORGE.     First  Report  of  the  Geological  Survey  of  Colorado,  1908. 
T.  L.  WALKER.     Report  on  Tungsten  Ores  of  Canada,  Department  of  Mines,  1909. 


VIII.  PHOSPHATES   AND  VANADATES. 
i.  APATITE;    ROCK  PHOSPHATE;   GUANO;   ETC. 

Phosphorus  is  one  of  the  most  widespread  of  the  elements,  and 
is  apparently  indispensable  to  both  animal  and  vegetable  life.  In 
nature  it  occurs  in  various  compounds,  by  far  the  more  common 
being  the  phosphates  of  calcium  and  aluminum,  such  as  are  com- 
mercially used  as  fertilizers.  These  in  various  conditions  of  im- 
purity occur  under  several  forms,  some  distinct  and  well  defined, 
others  illy  denned  and  passing  by  insensible  gradations  into  one 
another,  but  all  classed  under  the  general  term  of  phosphates. 
Their  origin  and  general  physical  properties  are  quite  variable,  and 
any  attempt  at  classifying  must  be  more  or  less  arbitrary.  For 
our  present  purposes  it  is  sufficient  that  we  treat  them  under  the 
heads  of  mineral  phosphates  and  rock  phosphates,  as  has  been 
done  by  Dr.  Penrose.1  These  two  classes  are  then  subdivided  as 
below : 

1  Bulletin  No.  46  of  the  U.  S.  Geological  Survey. 


PHOSPHATES.  267 

f  Anatites  \  Fluor-apatites 

/T.   __.         .    ,        .    .,  'es i  Chlor-apatites. 

(I)  Mineral  phosphates1...  \ 

[  Phosphorite. 

Amorphous  nodular  phosphates  loose 
or  cemented  into  conglomerates. 

Phosphatic  limestones. 
(II)  Rock  phosphates 1 

~,  (  Soluble  guanos. 

Guanos ]  Leached  guanos. 

Bone  beds. 

Apatite. — Under  the  name  of  apatite  is  included  a  mineral 
composed  essentially  of  phosphate  of  lime,  though  nearly  always 
carrying  small  amounts  of  fluorine  or  chlorine,  thereby  giving  rise 
to  the  varieties  fluor-apatite  and  chlor-apatite.  The  mineral  crystal- 
lizes in  the  hexagonal  system,  forming  well-defined  six-sided  elon- 
gated prisms  of  a  green,  blue,  yellow,  rose,  or  reddish  color,  or  some- 
times quite  colorless.  It  also  occurs  as  a  crystalline  granular  rock 
mass.  The  hardness  is  4.5  to  5;  specific  gravity,  3.23;  luster,  vitre- 
ous. Apatite  in  the  form  of  minute  crystals  is  an  almost  universal 
constituent  of  eruptive  rocks  of  all  kinds  and  all  ages.  It  is  also 
found  in  sedimentary  and  metamorphic  rocks  as  a  constituent  of  veins 
of  various  kinds,  and  is  a  common  accompaniment  of  beds  of  mag- 
netic iron  ores.  It  is  only  when  occurring  segregated  in  veins  and 
pockets,  either  in  distinct  crystals  or  as  massive  crystalline  aggre- 
gates, as  in  Canada  and  Norway,  that  the  material  has  any  great 
economic  value.  The  average  composition  of  the  apatites,  as  given 
in  the  latest  edition  of  Dana's  Mineralogy,  is  as  follows: 

1  Fuchs  (Notes  Sur  la  Constitution  des  Gites  Phosphate  de  Chaux)  divides  the 
natural  phosphates  into  three  classes.  In  the  first  the  phosphatic  material  is  concen- 
trated in  sedimentary  beds;  in  the  second  it  is  disseminated  throughout  eruptive 
rocks,  and  in  the  third  it  constitutes  entirely  or  partially  the  material  filling  veins 
and  pockets.  That  found  in  sedimentary  beds  occurs  in  rounded  and  concretionary 
masses  called  nodules.  In  eruptive  and  metamorphic  rocks  the  phosphate  occurs  in 
the  crystalline  form  of  apatite,  sometimes  isolated  or  grouped  in  aggregates.  In 
veins  the  phosphate  occurs  massive  and  in  pockets,  crystalline,  but  not  in  distinct 
crystals;  rather  as  globular  and  radiating  masses.  To  such  the  name  phosphorite  is 
given.  The  three  varieties  show  a  like  variation  in  solubility,  the  amorphous  phos- 
phates being  soluble  in  citrate  or  oxalate  of  ammonia  to  the  extent  of  30  to  50  per 
cent;  the  phosphorites  to  the  extent  of  only  15  to  30  per  cent,  and  the  apatite  scarcely 
at  all.  The  amorphous  phosphates  alone  have  proven  of  value  for  direct  application 
to  soils,  the  other  varieties  needing  previous  treatment  to  render  them  soluble. 


268 


THE   NON-METALLIC  MINERALS. 


Variety. 

P205. 

CaO. 

F. 

Cl. 

41  O 

^  8 

6.8 

or  Ca3P  O8,  89  4   +CaCl   10  6 

Kluor-apatite 

42  T. 

r  e  c 

3-8 

or  Ca.PoOs,  Q2.2c;  +  CaF    7  7s 

The  name  phosphorite  covers  a  material  of  the  same  composi- 
tion as  apatite,  but  occurring  in  massive  concretionary  and  mam- 
millary  forms.  The  name  was  first  used  by  Kirwan  in  describing 
the  phosphates  of  Estremadura,  Spain,  which  occur  in  veins  and 
pockety  masses  in  Silurian  schists,  as  noted  later. 

Rock  Phosphate. — The  general  name  of  rock  phosphate  is 
given  to  deposits  having  no  definite  composition  but  consisting 
of  amorphous  mixtures  of  phosphatic  and  other  mineral  matter 
in  indefinite  proportions.  Here  would  be  included  the  amorphous 
nodular  phosphates  like  those  of  our  Southern  Atlantic  States, 
phosphatic  limestones  and  marls,  guano,  and  bone-bed  deposits 
These  are  so  variable  in  character  that  no  satisfactory  description 
of  them  as  a  whole  can  be  given.  The  name  coprolite  is  given  to 
a  nodular  phosphate  such  as  occurs  among  the  Carboniferous  beds 
of  the  Firth  of  Forth  in  Scotland,  and  is  regarded  as  the  fossilized 
excrement  of  vertebrate  animals.  Phosphatic  limestones  and  marl, 
as  the  names  denote,  are  simply  limestones  and  marls  containing 
an  appreciable  amount  of  lime  in  the  form  of  phosphate.  Such  are 
rarely  sufficiently  rich  to  be  of  value  except  in  the  immediate  vicinity 
of  their  occurrence,  owing  to  cost  of  transportation.  Guano  is  the 
name  given  to  the  accumulations  of  sea-fowl  excretions,  such  as 
occur  in  quantities  only  in  rainless  regions,  as  the  western  coast 
of  South  America.  The  material  is  of  a  white-gray  and  yellowish 
color,  friable,  and  contains  some  20  or  more  per  cent  of  phosphate 
of  lime,  10  to  12  per  cent  of  organic  matter,  30  per  cent  of  ammonia 
salts,  and  20  per  cent  of  water.  Through  prolonged  exposure  to 
the  leaching  action  of  meteoric  waters,  similar  deposits  in  the  West 
India  Islands  have  lost  their  ammonia  salts  and  other  soluble  con- 
stituents and  become  converted  into  insoluble  phosphates,  or  leached 
guanos  like  those  of  the  Navassa  Islands. 

Origin  and  Occurrence. — The  origin  of  the  various  forms  of  phos- 
phatic deposits  has  been  a  subject  of  much  speculation.  Their 
occurrence  under  diverse  conditions  renders  it  certain  that  not  all 


PHOSPHATES  269 

can  be  traced  to  a  common  source,  but  are  the  result  of  different 
agencies  acting  under  the  same  or  different  conditions.  By  many, 
all  forms  are  regarded  as  being  phosphatic  materials  from  animal 
life,  and  owing  their  present  diversity  of  form  to  the  varying  con- 
ditions to  which  they  were  at  the  time  of  formation  or  have  since 
been  subjected.  This,  however,  as  long  since  pointed  out,  is  an 
uncalled-for  hypothesis,  since  phosphatic  matter  must  have  existed 
prior  to  the  introduction  of  animal  life,  and  there  is  no  reason  to 
suppose  it  may  not,  under  proper  conditions,  have  been  brought 
into  combination  as  phosphate  of  lime  without  the  intervention 
of  life  in  any  of  its  forms.  The  almost  universal  presence  of  apatite 
in  small  and  widely  disseminated  forms  in  eruptive  rocks  of  all 
kinds  and  all  ages  would  seem  to  declare  its  independence  of  animal 
origin  as  completely  as  the  pyroxenic,  feldspathic,  or  quartzose 
constituents  with  which  it  is  there  associated.  The  occurrence  of 
certain  of  the  Canadian  apatites  as  noted  later,  in  veins  and  pockets, 
sometimes  with  a  banded  or  concretionary  structure  and  blending 
gradually  into  the  country  rock,  is  regarded  by  some  as  strongly 
suggestive  of  an  origin  by  deposition  from  solution,  that  is,  by  a 
process  of  segregation  of  phosphates  from  the  surrounding  rock 
contemporaneously  with  their  metamorphism  and  crystallization. 

Dr.  Ells,  of  the  Canadian  survey,  would  regard  those  occurring 
in  close  juxtaposition  with  eruptive  pyroxenites  as  due  to  combina- 
tion of  the  phosphoric  acid  brought  up  in  vapors  along  the  line  of 
contact  with  the  calcareous  materials  in  the  already  softened  gneisses. 
This  explanation  as  well  as  others  will  perhaps  be  better  understood 
in  the  part  of  this  work  relating  to  localities.  On  the  other  hand, 
the  presence  of  apatite  in  crystalline  form  associated  with  beds  of 
iron  ore,  as  in  northern  New  York,  has  been  regarded  by  Prof. 
W.  P.  Blake  and  others  as  indicative  of  an  organic  and  sedimentary 
origin  for  both  minerals.  Later  work  has,  however,  shown  that 
these  ores  are  probably  of  igneous  origin.  The  Norwegian  apatite 
from  its  association  with  an  eruptive  rock  (gabbro)  has  been  regarded 
as  itself  of  eruptive  origin. 

The  phosphorites,  like  the  apatites,  occur  in  commercial  quan- 
tities mainly  among  the  older  rocks,  and  in  pockets  and  veins  so 
situated  as  to  lead  to  the  conclusion  that  they  are  secondary  products 


270 


THE  NON-METALLIC  MINERALS 


derived  by  a  process  of  segregation  from  the  inclosing  material. 
Davies  regards  the  Bordeaux  phosphorites,  in  the  Jurassic  lime- 
stones of  southern  France  as  the  result  of  phosphatic  matter  de- 
posited on  the  rocky  floor  of  an 
Eocene  ocean,  from  water  largely 
impregnated  with  it.  Others  have 
considered  them  as  geyserine 
ejections,  or  due  to  infiltration 
of  water  charged  with  phosphatic 
matter  derived  from  the  bones 
in  the  overlying  clays.  Stanier, 
on  the  other  hand,  regards  the 
phosphorites  of  Portugal  as  due 
to  segregation  of  phosphatic 
matter  from  the  surrounding 
granite,  the  solvent  being  meteoric 
FIG.  40.— Section  showing  apatite  de-  waters.  Such  deposits  are  super- 


posits in  Wallingford  Mica  Mine. 
(After  Cirkel) 


ficial  and  limited  to  those  por- 
tions of  the  rock  affected  by 
surface  waters. 

The  origin  of  the  amorphous,  nodular,  and  massive  rock  phos- 
phates can  be  traced  more  directly  to  organic  agencies.  All 
things  considered,  it  seems  most  probable  that  the  phosphatic 
matter  itself  was  contained  in  the  numerous  animal  remains,1  which, 
in  the  shape  of  phosphatic  limestones,  marls,  and  guanos,  have 
accumulated  under  favorable  conditions  to  form  deposits  of  very  con- 
siderable thickness.  Throughout  these  beds  the  phosphatic  matter 
would,  in  most  cases,  be  disseminated  in  amounts  too  sparing  to 
be  of  economic  value,  but  it  has  since  their  deposition  been  con- 
centrated by  a  leaching  out  by  percolating  waters  of  the  more  soluble 
carbonate  of  lime.  Thus  H.  Losne,  in  writing  of  the  nodular  phos- 
phates occurring  in  pockety  masses  in  clay  near  Doullens  (France), 


1  T.  S.  Hunt  showed,  in  1854,  that  shells  of  fossil  lingulae  were  largely  phosphatic, 
calcined  shells  of  L.  ovalis  yielding  85.79  per  cent  phosphate  of  lime.  American 
Journal  of  Science,  XVII,  1854,  p.  235. 


PHOSPHATES.  271 

argues  that  the  nodules  as  well  as  the  clay  itself  are  due  to 
the  decalcification  of  preexisting  chalk  by  percolating  meteoric 
waters. 

In  this  connection  it  is  instructive  to  note  that  phosphatic  nodules, 
in  size  rarely  exceeding  4  to  6  cm.,  were  dredged  up  during  the 
Challenger  expedition,  from  depths  of  from  98  to  1,600  fathoms 
on  the  Agulhas  Banks,  south  of  the  Cape  of  Good  Hope.  These 
are  rounded  and  very  irregular  capricious  forms,  sometimes  angular, 
and  have  exteriorly  a  glazed  appearance,  due  to  a  thin  coating  of 
oxides  of  iron  and  manganese.  The  nodules  yield  from  19.96  to 
23.54  per  cent  P2O5.  In  those  from  deep  water  there  are  found 
an  abundance  of  calcareous  organic  remains,  especially  of  rhizopods. 
The  phosphate  penetrates  the  shell  in  every  part,  and  replaces  the 
original  carbonate  of  lime. 

The  nodules  are  most  abundant  apparently  where  there  are 
great  and  rapid  changes  of  temperature  due  to  alternating  warm  and 
cold  oceanic  currents,  as  off  the  Cape  of  Good  Hope  and  the  eastern 
coast  of  North  America.  Under  such  conditions  marine  organisms 
would  be  killed  in  great  numbers,  and  by  the  accumulation  of  their 
remains  furnish  the  necessary  phosphatic  matter  for  the  nodules. 
It  seems  probable  that  the  Cretaceous  and  Tertiary  deposits  in 
various  parts  of  the  world  may  have  formed  under  similar  con- 
ditions. 

Hughes  has  described  1  phosphatic  coralline  limestones  on  the 
islands  of  Barbuda  and  Aruba  (West  Indies),  as  having  undoubtedly 
originated  through  a  replacement  of  the  original  carbonic  by  phos- 
phoric acid,  the  latter  acid  being  derived  from  the  overlying  guano. 
The  phosphatic  guano  has,  however,  now  completely  disappeared 
through  the  leaching  and  erosive  action  of  water,  leaving  the  coral 
rock  itself  containing  70  to  80  per  cent  phosphate  of  lime. 

Hayes*  regards  the  Tennessee  black  phosphates  as  due  to  the, 


1  Quarterly  Journal  of  the  Geological  Society  of  London,  XLI,  1885,  P-  80. 

2  Sixteenth  Annual  Report  of  the  U.  S.  Geological  Survey,   1894-95,  Pt.  4,  p.  620; 
Seventeenth  Annual  Report  U.  S.  Geological  Survey,  1895-96,  Pt.  2,  p.  22. 


272 


THE  NON-METALLIC  MINERALS. 


slow  accumulation  on  sea  bottoms  of  phosphatic  organisms  (Lin- 
gulae),  from  which  the  carbonate  of  lime  was  gradually  removed 
by  the  leaching  action  of  carbonated  waters,  leaving  the  less  soluble 
phosphate  behind.  The  white  bedded  phosphates  of  Perry  County, 
in  the  same  State,  are  regarded  as  a  product  of  secondary  replace- 
ment— that  is,  as  due  to  phosphate  of  lime  in  solution,  replacing 
the  carbonate  of  lime  of  preexisting  limestones,  as  in  the  case  noted 
above.  The  source  of  the  phosphoric  acid,  whether  from  the  over- 
lying Carboniferous  limestones  or  from  the  older  Devonian  and 
Silurian  rocks,  is  not,  however,  in  this  case  apparent. 

Teall  has  shown1  that  some  phosphatic  rocks  from  Clipperton 
Atoll,  in  the  northern  Pacific,  are  trachytes  in  which  phosphoric 
acid  has  replaced  the  original  silica.  The  replacement  he  regards 
as  having  been  effected  through  the  agency  of  alkaline  (principally 
ammonium)  phosphate  which  has  leached  down  from  overlying 
guano.  A  microscopic  examination  of  the  rock  in  thin  sections 
showed  that  the  replacing  process  began  with  the  interstitial  matter, 
then  extended  to  the  feldspar  microlites,  and  lastly  the  porphyritic 
sanidin  crystals.  The  gradual  change  in  the  relative  proportion 
of  silica  and  phosphoric  acid,  as  shown  by  analyses  of  more  or  less 
altered  samples,  is  shown  below,  No.  I  being  that  of  the  unaltered 
rock  and  II  and  III  of  the  altered  forms: 


Constituents. 

I 

II. 

III. 

SiO2 

CA  o 

43  7 

2  8 

PO 

D^  v 
8  4. 

17  O 

18  c 

jr-'e  .     .  . 

J-iOSS  on  ignition 

3-8 

12    T, 

2  7  o 

From  a  comparison  of  these  rocks  with  those  of  Redonda,  in 
the  Spanish  West  Indies,  it  is  concluded  that  the  latter  phosphates 
have  likewise  resulted  from  a  similar  replacement  in  andesitic  rocks. 
In  this  connection  reference  is  made  to  the  work  of  M.  A.  Gautier,2 


1  Quarterly  Journal  of  the  Geological  Society  of  London,  LIV,  1898,  p.  230. 

2  Formation  des  Phosphates  Naturels  d'Alumina  et  de  Fer,  Comptes  Rendus  de 
Academic  des  Sciences,  Paris,  CXVI,  1893,  p.  1491. 


PHOSPHATES.  273 

in  which  he  describes  the  formation  of  aluminous  phosphates  through 
the  action  of  the  ammonium  phosphate  arising  from  decomposing 
organic  matter  on  the  clay  of  the  floor  of  caverns.  (See  under 
Occurrences.) 

The  guanos,  as  noted  elsewhere,  owe  their  origin  mainly  to  the 
accumulations  of  sea-fowl  excretions.  Such  deposits  when  un- 
leached,  are  relatively  poor  in  phosphatic  matter  and  rich  in  salts 
of  ammonia.  Where,  however,  subjected  to  the  leaching  action 
of  rains  the  more  soluble  constituents  are  carried  away,  leaving 
the  less  soluble  phosphates,  together  with  impurities,  in  the  shape 
of  alumina,  silica,  and  iron  oxides  to  form  the  so-called  leached 
guanos  of  the  West  India  Islands.  As  stated  in  the  descriptions 
of  localities,  guano  deposits  are  not  infrequently  of  a  thickness 
such  as  to  cause  their  origin  as  above  stated  to  seem  well-nigh  in- 
credible were  there  not  sufficient  data  acquired  within  •  historic 
times  to  demonstrate  its  accuracy  beyond  dispute.  Thus  it  is  said  l 
that  in  the  year  1840  a  vessel  loaded  with  guano  on  the  island  of 
Ichabo,  on  the  east  coast  of  Africa.  During  the  excavations  which 
were  necessary  the  crew  exhumed  the  dead  body  of  a  Portuguese 
sailor,  who,  according  to  the  headboard  on  which  his  name  and 
date  of  burial  had  been  carved  with  a  knife,  had  been  interred 
fifty-two  years  previously.  The  top  of  this  headboard  projected 
2  feet  above  the  original  surface,  but  had  been  covered  by  exactly 
7  feet  of  subsequent  deposit  of  guano.  That  is  to  say,  the  deposition 
was  going  on  at  the  rate  of  a  little  over  an  inch  and  a  half  yearly. 

LOCALITIES   OF   PHOSPHATES. 

(i)  Mineral  Phosphates. 

Canada. — According  to  Dr.  Ells,  of  the  Canadian  Survey,3  the 
discovery  of  apatite  in  the  Laurentian  rocks  of  Eastern  Canada  was 
first  made  in  the  vicinity  of  the  Lievre  by  Lieutenant  Ingall  in  1829, 
though  it  was  not  until  early  in  1860  that  actual  mining  was  begun. 


1  R.  Ridgway,  Science,  XXI,  1893,  p.  360. 

3  The  Canadian  Mining  and  Mechanical  Review,  March,  1893. 


274 


THE  NON-METALLIC  MINERALS 


The  mineral  occurs  in  the  form  of  well-defined  crystals  in  a  matrix 
of  coarsely  crystalline  calcite  and  in  vein-like  and  pockety  granular 
masses  along  the  line  of  contact  between  eruptive  pyroxenites  and 
Laurentian  gneisses.  The  first  form  is  the  predominant  one  for 
Ontario  only,  the  second  for  Quebec.  From  a  series  of  openings 
made  at  the  North  Star  Mine,  in  the  region  north  of  Ottawa,  it 
appears  that  the  massive  coarsely  crystalline  granular  apatite  follows 
a  somewhat  regular  course  in  the  pyroxenite  near  the  gneiss,  but 
occurs  principally  in  a  series  of  large  bunches  or  chimneys  connected 
writh  each  other  by  smaller  strings  or  leaders.  Sometimes  these 
pockety  bunches  of  ore  are  of  irregular  shape  and  yield  hundreds 
of  tons,  but  present  none  of  the  characteristics  of  veins,  either  in 
the  presence  of  hanging  or  foot  walls,  while  many  of  the  masses  of 
apatite  appear  to  be  completely  isolated  in  the  mass  of  pyroxenite, 
though  possibly  there  may  have  been  a  connection  through  small 
fissures  with  other  deposits.  The  lack  of  any  connection  between 
these  massive  apatites  and  the  regularly  stratified  gneiss  is  evident, 


FIG.  41. — Section  through  apatite  and  mica  deposits.  Templeton,  Canada. 

[After  Cirkel.] 

and  their  occurrence  in  the  pyroxenite  is  further  evidence  in  support 
of  the  view  that  the  workable  deposits  are  not  of  organic  origin, 
but  confined  entirely  to  igneous  rocks.  In  certain  cases  where  a 
supposed  true- vein  structure  has  been  found,  such  can  be  explained 
by  noticing  that  the  deposits  of  phosphates  occur,  for  the  most 
part  at  least,  near  the  line  of  contact  between  the  pyroxenite  and 
the  gneiss.  (Fig.  41.) 


PHOSPHATES. 


275 


The  principal  producing  fields  lie  in  Ottawa  County,  Province 
of  Quebec,  and  Leeds,  Lanark,  Frontenac,  Addington,  and  Renfrew 
counties,  Province  of  Ontario.  The  first,  which  is  by  far  the  more 
important  field,  extends  from  the  Ottawa  River  on  the  south,  in  a 
northerly  direction  through  Buckingham,  Templeton,  Wakefield, 
Denholm,  Bowman,  Hincks,  and  other  townships  with  an  average 
width  of  15  to  25  miles.  It  is  therefore  practically  coincident  with 
the  mica  (phlogopite)  belt.  The  second  lies  to  the  southwest  and 
extends  from  the  Ottawa  for  a  distance  of  about  100  miles  southerly, 
or  to  within  15  miles  of  the  St.  Lawrence.  It  has  a  width  of  from 
50  to  75  miles. 

Davies  gives  the  following  table  as  showing  the  average  composi- 
tion of  the  Canadian  phosphates: 


Constituents. 

I. 

II. 

III. 

IV. 

V. 

VI. 

Mqisture,  water  of  combination,  and  loss 
on  ignition 

0.62 

O.IO 

O.II 

I.OO 

0.80 

1.83 

Phosphoric  acid                    

33.  Cl 

41.  C4 

37.68 

30.84 

32.^3 

31.87 

Lime                                                       ... 

46.14 

^4.74 

SI.  04 

42.72 

44.26 

43.62 

Oxide  of  iron,  alumina)  fluorine,  etc.  — 
Insoluble  siliceous  matter  

7-83 

II.OO 

3-°3 

O.NO 

6.88 
4.20 

I3'32 

12.03 

12.15 

10.17 

9.28 

17.  tQ 

Equal  to  tricalcic  phosphate  of  lime. 

100.00 
75.  ir 

IOO.OO 

00.68 

100.00 

82.  2c; 

IOO.OO 
67.  T.2 

IOO.OO 
7I.OI 

100.10 
6O.-2C 

Norway. — The  principal  apatite  fields  lie  along  the  coast  in  the 
southern  portion  of  the  peninsula  between  Langesund  and  Arendal. 
The  material  occurs  in  crystals  and  crystalline  granular  aggregates 
of  a  white,  yellow,  greenish,  or  red  color  in  veins  and  pockets  em- 
bedded in  the  mass  of  an  eruptive  gabbro,  near  the  line  of  contact 
of  the  gabbro  and  adjacent  rocks,  in  the  country  rock  itself  in  the 
immediate  vicinity  of  the  gabbro,  and  in  coarse  pegmatitic  veins 
which  are  cut  by  the  gabbro.  The  largest  veins  are  in  the  mass 
of  the  gabbro  itself  or  near  the  line  of  contact.  Where  the  apatite 
occurs  in  the  gabbro  the  latter  is,  as  a  rule,  altered  into  a  hornblende 
scapolite  rock.  The  principal  associated  minerals  are  quartz, 
mica,  tourmaline,  scapolite,  feldspars,  rutile,  and  magnetic  and 
titanic  iron  and  sulphides  of  iron  and  copper.  The  country  rock 
is  gneiss,  schist,  and  granite.  The  mineral  belongs  to  the  variety 


276 


THE  NON-METALLIC  MINERALS. 


called  fluor-apatite,  as  shown  by  the  following  analysis  from  Dr. 
Penrose's  Bulletin: 


APATITE   FROM  ARENDAL. 


Constituents. 

Per  Cent. 

Phosphoric  acid  (P2O5)  l  
Fluorine  2             

42.229 
?    A.IC 

Chlorine  3     

O.<12 

Lime  (CaO) 

AQ     06 

Calcium 

3      88/1 

IOO.OOO 

The  Norway  apatites  have  been  mined  according  to  Penrose 
since  1854,  the  earliest  workings  being  at  Kragero.  According  to 
Davies,  however,  the  discovery  of  deposits  that  could  be  profitably 
worked  dates  only  from  1871.  The  distribution  of  the  material 
is  very  uncertain  and  irregular,  and  the  value  of  the  deposits  can 
not  be  foretold  with  any  great  approximation  to  accuracy.  A 
large  mass  of  this  material,  weighing  nearly  2  tons,  is  on  exhibition 
in  the  National  Museum  at  Washington. 

Spain. — Important  deposits  of  phosphorites  occur  between 
Logrosan  and  Caceres,  in  Estremadura  Province.  The  deposits  are 
in  the  form  of  pockets  and  veins  in  slates  and  schists  supposed  to 
be  of  Silurian  age;  at  times  a  vein  is  found  at  the  line  of  contact 
between  the  slate  and  granite.  The  veins  vary  in  thickness  from  i 
to  several  feet,  the  largest  being  some  20  feet  and  extending  for  over 
2  miles.  This  is  by  far  the  largest  of  its  kind  known.  As  described, 
the  Logrosan  phosphate  has  a  subcrystalline  structure;  sometimes 
fibrous  and  radiating.  It  is  soft  and  chalky  to  the  touch,  easily 
broken,  but  difficult  to  grind  into  a  fine  powder.  An  examination 
under  the  microscope  exhibits  conchoidal  figures,  interrupted  with 
spherical  grains,  devoid  of  color  and  opaque. 

The  highest-grade  material  is  rosy  white  or  yellowish  white 
in  color,  soft,  concentric,  often  brilliantly  radiated,  with  a  mam- 

1  Equal  92.189  per  cent  tricalcic  phosphate. 

2  Equal  7.01  per  cent  fluoride  of  calcium. 

3  Equal  0.801  per  cent  chloride  of  calcium. 


PHOSPHATES. 


277 


millary  or  conchoidal  surface.  Red  spots  from  iron  and  beautiful 
dendrites  of  manganese  are  not  infrequent.  The  poorer  qualities 
are  milky  white,  vitreous,  hard,  and,  though  free  from  limestone, 
contain  considerable  silica. 

In  the  Caceres  district  the  phosphorites  occur  not  in  veins,  but 
rather  in  pockety  masses  in  veins  of  quartz  and  dark-colored  lime- 
stone, which  are  found  cutting  both  the  granite  and  slate. 

The  following  analyses  from  Dr.  Penrose's  paper  show  about  the 
average  composition  of  these  phosphorites: 


LOGROSAN. 


Constituents. 

Per  Cent. 

Silica  

I    70 

Protoxide  of  iron  

•2,  1C 

Fluoride  of  lime  

I4.OO 

Phosphate  ol  lime  

Si.is 

CACERES. 


Constituents. 

Per  Cent. 

Insoluble  siliceous  matter  
Water  expelled  at  a  red  heat.  .  .  . 
Phosphate  of  lime  

21.05 
3.00 
72.  IO 

Loss,  iron  oxides,  etc  

3.8S 

Portugal. — Phosphorites  occur  in  Silurian  and  Devonian  rocks 
under  similar  conditions  to  those  of  Spain  in  Estremadura,  Alemetjo, 
and  Beira  provinces,  and  which  need,  therefore,  no  further  notice 
here.  Stanier,1  however,  describes  a  variety  found  in  pockety  and 
short  veinlike  masses  which  are  worthy  of  a  passing  notice.  These 
occur  not  in  schists  and  sedimentary  rocks  but  in  massive  granites. 
They  are  found  mainly  in  the  superficial  portions,  where  the  granite 
has  weathered  away  to  a  coarse  sand,  and  in  short  gash-like  veins 
and  pockets  of  slight  width  and  extent.  The  phosphatic  material 
is  described  as  of  a  milk-white  color,  opaque,  and  showing  when 


1  Les  Phosphorites  du  Portugal,  Annales  de  la  Societe  Geologique  de  Belgique, 
XVII,  1890,  p.  223. 


278  THE    NON-METALLIC  MINERALS. 

broken  open  a  palmately  radiating  structure,  like  hoarfrost  upon 
a  window  pane.  As  a  rule  the  masses  when  found  are  enveloped 
in  a  thin  coating  of  kaolin-like  material  supposed  to  be  derived 
by  decomposition  from  the  feldspar  of  the  granites.  They  are 
mined  only  from  open  cuts  and  in  the  superficial  more  or  less  de- 
composed portions  of  the  rock,  to  which  they  are  believed  to  be 
mainly  limited,  having  originated,  as  elsewhere  indicated,  through 
a  segregation  of  the  phosphatic  material  dissolved  by  meteoric 
waters  from  the  surrounding  granite  and  subsequently  depositing 
it  in  pre-existing  fissures.  The  percentage  of  tricalcic  phosphate  is 
given  as  varying  between  60  and  80  per  cent. 

(2)  Rock  Phosphates. 

United  States. — Nodular  phosphatic  deposits  are  found  at  inter- 
vals all  along  the  Atlantic  coast  of  the  United  States,  from  North 
Carolina  down  to  the  southern  extremity  of  Florida.  The  North 
Carolina  deposits  occur  principally  in  the  counties  of  Sampson, 
Duplin,  Fender,  Onslow,  Columbus,  and  New  Hanover,  all  in  the 
southeastern  part  of  the  State.  The  deposits  are  of  two  kinds:  (i)  a 
nodular  form  overlying  the  Eocene  marls  and  consisting  of  phos- 
phate nodules,  sharks'  teeth,  and  bones  embedded  in  a  sandy  or 
marly  matrix,  and  (2)  as  a  conglomerate  of  phosphate  pebbles,  sharks' 
teeth,  bones,  and  quartz  pebbles,  all  well  rounded  and  cemented 
together  along  with  grains  of  greensand  in  a  calcareous  matrix. 

The  beds  of  the  first  variety  usually  overlie  strata  of  shell  marl, 
though  this  is  sometimes  replaced  by  a  pale  green  indurated  sand. 
The  two  following  sections  will  serve  to  illustrate  their  mode  of 
occurrence : 

SAMPSON   COUNTY.  DUPLIN   COUNTY. 

(1)  Soil,  sand,  or  clay,  5  to  10  feet.  (i)  Sandy  soil,  I  to  10  feet. 

(2)  Shell  marl,  5  to  10  feet.  (2)  Nodule  bed,  i  to  2  feet. 

(3)  Bed  with  phosphate  nodules,  i  to  3     (3)  Shell  marL 

feet. 

(4)  Sea-green  sandy  marl,  2  to  4  feet. 

(5)  Ferruginous  hardpan,  6  to  12  inches. 

(6)  Interstratified  lignites  and  sands  as 

in  (4). 


PLATE  XXVI. 

Map  of  the  Florida  Phosphate  Regions. 
[After  G.  H.  Eldridge,  U.  S.  Geological  Survey.] 

[Facing  page  278.] 


PHOSPHATES.  279 

The  nodules  are  of  a  lead-gray  color,  varying  in  size  from  that 
of  a  man's  fist  to  masses  weighing  several  hundred  pounds.  In 
texture  they  vary  from  close,  compact  and  homogeneous  masses  to 
coarse-grained  and  highly  siliceous  rocks  distinguished  by  con- 
siderable quantities  of  sand  and  quartz  pebbles  sometimes  the  size  of 
a  chestnut.  Occasionally  the  nodules,  which  as  a  rule  are  of  an 
oval  flattened  form,  contain  Tertiary  shells.  The  second  or  con- 
glomerate variety  occurs  mainly  in  New  Hanover  and  Fender 
counties,  the  beds  in  some  instances  being  6  feet  in  thickness,  though 
usually  much  less.  The  following  section,  taken  from  Dr.  Penrose's 
Bulletin,  shows  their  position  and  association  as  displayed  at  Castle 
Hayne,  New  Hanover  County. 

"(i)  White  sand,  o  to  3  feet. 

"  (2)  Brown  and  red  ferruginous  sandy  clay,  or  clayey  sand,  I 
to  3  feet. 

"(3)  Green  clay,  6  to  12  inches. 

"(4)  Dark-brown  indurated  peat,  3  to  12  inches. 

"(5)  White  calcareous  marl,  o  to  2  feet. 

"(6)  White  shell  rock,  o  to  14  inches. 

"(7)  Phosphatic  conglomerate,  i  to  3  feet. 

"(8)  Gray  marl  containing  smaller  nodules  than  the  overlying 
beds,  2j  to  4^  feet. 

"  (9)  Light-colored,  calcareous  marl,  containing  nodules  which 
are  smaller  than  those  in  the  overlying  beds,  which  grow  fewer  and 
smaller  at  a  depth.  Many  shells." 

The  phosphatic  nodules  in  this  conglomerate  are  kidney  and  egg 
shaped  and  sometimes  make  up  as  much  as  three-fourths  the  contents 
of  a  bed;  usually,  however,  the  proportion  is  smaller,  and  sometimes 
there  are  none  at  all.  The  mass  as  a  whole  does  not  contain  more 
than  10  to  20  per  cent  phosphate  of  lime,  but  it  is  said  to  have  been 
successfully  used  as  a  fertilizer.  The  individual  nodules  may  be  richer 
in  phosphatic  matter  on  the  outer  surface  than  toward  the  center. 

Aside  from  the  phosphatic  layer  as  described  above,  phosphatic 
nodules  are  found  in  large  quantities  in  the  beds  of  rivers  of  these 
districts,  where  they  have  accumulated  through  the  washing  action 
of  flowing  water,  the  finer  sand,  clay,  and  gravel  having  been  carried 
away.  Such  phosphates  naturally  do  not  differ  materially  from 


280  THE  NON-METALLIC  MINERALS. 

those  on  land  except  that  they  are  darker  in  color  and  sometimes 
more  siliceous. 

The  deposits  of  South  Carolina  are  of  the  same  nature  as  those 
described  above  but  of  low  grade.  For  many  years  they  were  more 
generally  used  than  any  other  American  phosphate.  This  was  due 
not  only  to  the  cheapness  of  the  material  but  to  the  many  good 
qualities  of  the  low-grade  acid  phosphate  made  from  it.  Of  late 
years  the  Florida  phosphates  have  gradually  replaced  them. 

Phosphates  in  the  form  of  nodules  and  phosphatic  marls  and 
green  sands  occur  in  Alabama  in  both  the  Tertiary  and  Cretaceous 
formations.  Their  geographical  distribution  is  therefore  limited 
to  areas  south  of  the  outcrops  of  the  lowest  Cretaceous  beds  which 
stretch  in  a  curve  from  the  northwest  corner  of  the  State  across 
near  Fayette  Courthouse,  Tuscaloosa,  Centerville,  and  Wetumpka, 
to  Columbus,  Georgia.  As  all  the  Cretaceous  and  Tertiary  beds 
have  a  dip  toward  the  Gulf  of  from  25  to  40  feet  to  the  mile,  the 
phosphate-bearing  strata  appear  at  the  surface  in  a  comparatively 
narrow  belt  along  the  line  above  indicated  and  are  to  be  found  only 
at  gradually  increasing  depths  below  at  points  to  the  southward. 

Although  selected  nodules  may  run  as  high  as  27  per  cent  of 
phosphoric  acid,  and  marls  as  high  as  6.7  per  cent,  the  Tertiary 
is  not  regarded  by  Professor  Smith  as  a  promising  source  of  com- 
mercial phosphates  in  the  State. 

The  principal  phosphate  region  of  Florida,  as  known  to-day, 
comprises  an  area  extending  from  west  of  the  Apalachicola  River 
eastward  and  southward  to  nearly  50  miles  south  of  Caloosahatchee 
River,  as  shown  on  the  accompanying  map.1  According  to  Mr. 
Eldridge,  the  deposits  comprise  four  distinct  and  widely  different 
classes  of  commercial  phosphates,  each  having  a  peculiar  genesis, 
a  peculiar  form  of  deposit,  and  chemical  and  physical  properties 
such  as  readily  distinguish  it  from  any  of  the  others. 

According  to  their  predominant  characteristics  or  modes  of  occur- 
rence, these  classes  have  come  to  be  known  as  hard-rock  phosphates, 
soft  phosphate,  land  pebble  or  matrix  rock,  and  river  pebble.  With 
the  exception  of  the  soft  phosphates,  they  underlie  distinct  regions, 

1  Preliminary  sketch  of  Phosphates  of  Florida,  by  George  H.  Eldridge. 


PHOSPHATES.  281 

each  class  being  separate  or  but  slightly  commingling  with  one 
another.  The  hard-rock  phosphate  is  a  hard,  massive,  close- 
textured,  homogeneous,  light-gray  rock,  showing  large  and  small 
irregular  cavities,  which  are  usually  lined  with  secondary  mam- 
millary  incrustations  of  nearly  pure  phosphorite. 

The  deposits,  which  average  some  36.65  per  cent  P2O5,  lie  in 
Eocene  and  Miocene  strata,  occurring  in  the  first  named  as  a  bowlder 
deposit  in  a  soft  matrix  of  phosphatic  sands,  clays,  and  other  material, 
resulting  from  the  disintegration  of  the  hard  rock  and  constituting 
the  soft  phosphates.  They  underlie  sands  of  from  10  to  20  feet  in 
thickness,  and  have  been  penetrated  to  a  depth  of  60  feet.  The 
phosphate  deposit  proper  is  white,  the  bowlders  of  rounded  and 
irregular  outline,  varying  in  diameter  from  2  or  3  inches  to  10  feet. 
None  of  the  hard-rock  deposits  of  the  Eocene  originated  in  the 
positions  they  now  occupy.  The  Miocene  hard-rock  phosphates, 
on  the  other  hand,  lie  in  regular  bedded  deposits  in  situ,  as  well  as 
in  bowlders.  The  beds  lie  horizontal  but  a  few  feet  below  the  sur- 
face, being  covered  only  by  superficial  sand.  They  are,  as  a  rule, 
but  from  4  feet  to  5  feet  thick.  The  name  soft  rock,  or  soft  phos- 
phate, as  above  indicated,  is  given  to  the  softer  material  associated 
with  the  hard  rock,  which  in  part  results  from  the  disintegration 
of  the  last  named.  It  is  also  applied  somewhat  loosely  to  any 
variety  not  distinctly  hard.  It  varies  greatly  in  color,  chemical  and 
physical  characteristics,  and  rarely  carries  more  than  20  to  25  per 
cent  of  P2O5. 

The  name  land-pebble  phosphate  includes  pebbles  from  deposits 
consisting  of  either  earthy  material  carrying  fossil  remains,  grains 
of  quartz,  and  pisolitic  grains  of  lime  phosphate,  or  of  a  material 
resembling  in  texture  and  other  characteristics  the  hard-rock  phos- 
phate. The  individual  pebbles  vary  in  size  up  to  that  of  the  English 
walnut,  are  normally  white,  but  wrhen  subjected  to  percolating  water 
become  dark  gray  or  nearly  black.  The  exteriors  are  quite  smooth 
and  glossy;  such  yield  on  an  average  some  30  to  35  per  cent  P2O5. 

The  river-pebble  varieties  differ  from  the  last  mainly  in  mode 
of  occurrence,  being  found,  as  the  name  would  indicate,  in  the  beds 
of  streams,  where  presumably  they  have  accumulated  through  the 
washing  away  of  finer  and  lighter  materials.  They  are  most  abun- 


282  THE  NON-METALLIC  MINERALS. 

dant  in  the  Peace,  Caloosahatchee,  Alafia,  and  other  rivers  entering 
the  Gulf  south  of  Tampa  and  Hillsborough  bays,  though  the  Withla- 
coochee,  Aucilla,  and  rivers  of  the  western  part  of  the  State,  carry 
also  a  mixture  of  pebbles,  hard-rock  fragments,  and  bones  derived 
from  the  various  strata  through  which  they  have  cut  their  channels. 
The  pebbles  of  the  Western  rivers  show  a  very  uniform  composition, , 
and  range  from  25  to  30  per  cent  phosphoric  anhydride  (P2O5),  or 
about  65  per  cent  of  phosphate  of  lime,  the  impurities  being  mainly 
siliceous  matter,  carbonate  of  lime,  alumina,  and  iron  oxides. 

Phosphatic  deposits  of  high  grade  and  covering  considerable 
areas  in  western  middle  Tennessee  were  discovered  during  the 
latter  part  of  1893.  Since  then  development  has  been  rapid,  and 
the  State  now  stands  second  in  rank,  as  a  producer,  being  exceeded 
only  by  Florida.  The  general  distribution  of  the  beds  is  shown 
in  the  accompanying  sketch  map  (Fig.  42),  while  their  varying 
thickness  is  shown  in  the  columnar  sections  on  PI.  XXVII.  The 
essential  facts  regarding  these  deposits  have  been  summarized  by 
C.  W.  Hayes  l  from  whose  reports  a  large  part  of  the  material  here 
given  is  compiled.  The  deposits  are  classified  as — 
I.  Black  phosphate  (an  original  deposit). 

1.  Nodular. 

2.  Bedded,  including  oolitic,  compact  conglomeratic,  and 

shaly  varieties. 
II.  White  phosphate   (a  secondary  deposit). 

1.  Stony. 

2.  Breccia. 

3.  Lamellar. 

The  first  of  these,  the  black  phosphate,  is  of  Devonian  age. 
The  second,  the  white  phosphates,  which  are  altogether  secondary 
deposits,  are  very  recent.  The  surface  rocks  of  the  region  include 
Silurian,  Devonian,  and  Carboniferous  beds  arranged  as  follows: 

Carboniferous Cherty,  shaly  limestone. 

D  Greensand  with  phosphatic  nodules..  8-14  inches 
C  Carbonaceous  black  shale 0-6    feet 

Devonian j  B  Bedded  phosphate 0-40  inches 

A  Gray  sandstone 0-6    feet 

Silurian Blue  limestone 

1  See  i6th,  lyth,  and  2ist  Annual  Reports,  U.  S.  Geological  Survey. 


Scale:  i  inch=io  feet. 


TOTTYS  BEND, 
HICKMAN  COUNTY. 


Calcareous 
cherty  shale. 


_  Blue  shale 

with  phosphate 

nodules. 

Black  shale. 

Oolitic  phos- 
phate,gray,  40". 
Oolitic  phos- 
phate, blue. 
Phosphatic 
limestone,  18". 


Blue  flaggy 
limestone. 


Calcareous 
cherty  shale. 


Black  shale. 


Phosphatic 
sandstone 
and  conglom- 
erate, 22". 


Blue  flaggy 
limestone. 


FALL  BRANCH, 
HICKMAN  COUNTY. 


Calcareous 
cherty  shale. 


Black  shale 

with  beds  of 

phosphatic 

nodules. 


Oolitic  phos- 
phate, 36",  with 
conglomerate 
streaks. 


Phosphatic 
limestone. 


Blue  flaggy 
limestone. 


_  Cherty 
limestone. 


Black  shale. 


Black  sandy 
phosphate.  20" 
Gray  sand- 
stone. 
Chert  nodules. 

Calcareous 
sandstone. 


Blue  flaggy 
limestone. 


CENTERVILLE, 
HICKMAN  COUNTY. 


Calcareous 
cherty  shale. 


Black  shale. 


Black  phos- 
phate,  2,S". 

Blue  clay 
shales. 


Blue  flaggy 
limestone. 


.  Cherty 
Emestone. 


Black  shale 

with  phosphate 

nodules. 


Black  shaly, 
sandy  phos- 
phate, 54". 

Yellow  sandy 
shale. 


Massive  gray 
sandstone. 


Blue  flaggy 
limestcne. 


PLATE  XXVII. 

Sections  through  the  Tennessee  Phosphate  Beds. 
[After  C.  W.  Hayes,  U.  S.  Geological  Survey.] 

[Facing  page  282.] 


PHOSPHATES. 


283 


36 


30 


35  — J 


35 


87 c 


SCALE  OF  MILES 


FIG.  42.  —  Map  of  Tennessee  phosphate  region. 
[After  C.  W.  Hayes,  iyth  Ann.  Rep.  U.  S.  Geological  Survey.] 


284  THE  NON-METALLIC  MINERALS. 

The  black  nodular  phosphate  occurs  in  a  black  shale,  in  spher- 
ical to  broadly  oval  and  flattened  ellipsoidal  forms,  with  smooth 
surfaces  and  black  color.  They  are  easily  detached  from  the  matrix 
and  weather  down  rapidly  to  a  gray,  at  times  almost  white,  sand. 
Their  distribution  is  extremely  irregular  and  they  have  not  yet  been 
found  in  sufficient  abundance  to  be  profitably  mined,  although 
individual  nodules  may  contain  from  60  to  70  per  cent  phosphate  of 
lime. 

The  black  bedded  phosphate  lies  immediately  beneath  the 
black  shale  containing  the  phosphate  nodules  just  noted  and  over- 
lying a  compact  Silurian  limestone.  It  is  evident  that  it  represents 
a  residual  accumulation  of  the  less  soluble  portions  of  preexisting 
limestones  which  has  been  rearranged  and  stratified  during  a  sub- 
sequent period  of  depression  of  the  land,  and  finally  covered  by 
the  sediments  now  forming  the  black  shale.  The  beds  lie  nearly 
horizontally  and  are  now  exposed  only  where  creeks  have  cut  through 
in  the  ordinary  processes  of  erosion.  As  noted  above,  it  occurs  in 
several  varieties.  The  oolitic  form  has  in  the  weathered  outcrop  the 
appearance  of  a  rusty  porous  sandstone.  A  close  inspection  of  the 
unweathered  rock  shows  it  to  be  made  up  of  rounded  or  flattened 
ovules  of  a  blue-black  color  and  small  fossil  shells  or  casts  of  shells 
embedded  in  a  fine-grained  or  structureless  matrix  which,  like  the 
ovules,  is  composed  mainly  of  phosphatic  material  made  dark  by 
carbonaceous  matter. 

The  compact  phosphate  variety  resembles  a  fine-grained  car- 
bonaceous sandstone.  When  fresh  it  is  of  a  dark  gray  to  bluish- 
black  color,  but  weathers  to  a  buff  or  dull  yellow  color,  natural 
joint  blocks  when  broken  across  often  showing  a  nearly  black  nucleal 
portion  surrounded  by  concentric  shells  of  oxidized  material  of 
varying  shades  of  brown  or  yellow.  Under  the  microscope  this 
variety  is  seen  to  be  made  up  of  small  ovules  and  fossil  casts  closely 
packed  together  without  the  amorphous  matrix  noted  in  the  oolitic 
variety. 

Closely  associated  with  the  above  forms  is  the  conglomeratic 
variety  consisting  of  beds  of  coarse  sandstone  and  conglomerate 
containing  varying  amounts  of  phosphate.  These  are  black  in  color 
and  weather  brownish,  also.  The  truly  phosphatic  portion  of  this 


ps  ^ 

C/5    C/3    <^ 


i.  "a 
l-a 

If 


2> 

c> 
5- 

&5 

t 

<*5 


•s,"'     \'  -m 
\\  \       i " 


I>  1 1 


PHOSPHATES.  285 

variety  resembles  that  of  the  compact  and  oolitic  forms,  but 
it  differs  in  the  presence  of  varying  amounts  of  quartz  sand  and 
pebbles. 

These  three  varieties  of  the  black  bedded  phosphate  are  stated 
to  yield  on  the  average  some  70  per  cent  of  phosphate  of  lime.1 
The  shaly  variety  is  poorer  in  phosphoric  acid  and  has  the  appearance 
of  a  dark  gray  to  black  shaly  sandstone.  The  distribution  of  the 
black  and  blue-black  phosphate  is  limited  mainly  to  Hickman, 
Lewis,  and  Perry  counties,  the  beds  varying  in  thickness  from  o  to 
48-  inches. 

The  white  phosphates  are  associated  with  Carboniferous  rocks, 
though  the  formation  of  the  phosphate  itself  is  much  more  recent. 
The  stony  variety,  as  it  is  called  above,  is  a  finely  granular  gray 
rock  sometimes  resembling  a  quartzitic  sandstone,  which  occurs 
in  more  or  less  regular  bands  alternating  with  thinner  bands  of 
chert  in  a  dark  shaly  siliceous  limestone.  Thin  sections,  under  the 
microscope,  show  a  ground  mass  of  chalcedonic  silica  inclosing 
numerous  very  minute  isotropic  forms  with  the  rhombic  outlines  of 
calcite  but  which  chemical  tests  show  to  be  phosphate.  This  variety 
yields  from  27  to  33  per  cent  phosphate  of  lime,  Ca3(PO4)2.  The 
breccia  phosphate  occurs  in  irregular  masses  composed  of  small, 
angular  fragments  of  the  chert  embedded  in  a  matrix  of  the  lime 
phosphate,  the  chert  fragments  varying  in  diameter  from  a  fraction 
of  an  inch  to  3  or  4  inches.  The  lamellar  variety  consists,  as  the 
name  suggests,  of  thin  parallel  plates  or  layers,  sometimes  several 
inches  in  width  of  phosphatic  material. 

The  white  phosphate  is  limited  in  its  distribution  to  an 
area  of  about  12  square  miles  in  the  northern  part  of  Perry 
County. 

In  addition  to  the  above  Hayes  has  described  2  a  brown  residual 
phosphate  occurring  in  the  form  of  a  "  blanket  "  deposit  (see  Fig.  43), 
immediately  underlying  the  surface  soil  and  overlying  Silurian  and 
Devonian  limestones,  in  Hickman,  Williamson,  Maury,  and  Lewis 


1  The  author's  investigations  led  him  to  place  the  average  considerably  lower, 
selected  samples  yielding  but  from  50  to  66  per  cent  Ca3(PO^3. 

2  Columbia  Folio,  No.  95,  U.  S.  Geological  Survey,  1903. 


286 


THE  NON-METALLIC  MINERALS. 


counties  of  the  same  State.  The  material  plainly  results  from  the 
weathering  of  the  surface  rocks,  the  prevailing  lime  carbonate 
being  carried  away  in  solution  while  the  phosphatic  and  other  less 
soluble  constituents  remain.  The  amount  of  phosphate  naturally 
varies  with  the  amount  of  leaching  the  beds  have  undergone  and 
their  content  of  insoluble  constituents.  Thicknesses  of  30  feet, 


(a)   Blanket   deposit  formed  on  broad  level  outcrop.     Shows  sagging  of  leached  phosphatic 
limestone  between  unleached  portions  (''  horses  ")  of  the  limestone. 


(6)  Collar  deposit  formed  on  steep  slope  by  surface  leaching  of  the  limestone.     Shows  also 
overplaced  deposit  covering  the  edges  of  underlying  nonphosphatic  limestone. 

FIG.  43, — Sections  showing  mode  of  occurrence  and  formation  of  residual  phosphates 

in  Tennessee. 
[After  C.  W.  Hayes,  U.  S.  Geological  Survey.] 

carrying  from  70  per  cent  to  80  per  cent  or  phosphate  of  lime,  are 
reported. 

Phosphatic  limestones  of  Ordovician  age  have  a  wide  geographic 
distribution  throughout  northern  Arkansas,  and  have  been  developed 
on  a  commercial  scale  on  Laflerty  Creek,  in  the  western  part  of 
Independence  County.  The  following  section  of  the  bed  is  given 
by  Purdue : l 

1  Bulletin  No.  315;  U.  S.  Geological  Survey,  1906,  p.  469. 


PHOSPHATES.  287 

ST.  CLAIR  LIMESTONE. 

Ft.  In. 

Brown  and  black  shale 2  o 

Low-grade  manganiferous  iron o  15 

Green  to  dark  clay  shale o  14 

High-grade  phosphate 4^  to  6  o 

Manganiferous  iron  ore - o  2 

Low-grade  phosphate 4  ° 

Polk  Bayou  limestone o  o 

The  upper  bed  phosphate  only  is  worked,  the  lower  being  of 
too  poor  grade.  The  better  class  cf  rock  is  described  as  light  gray 
in  color,  compact  and  homogeneous,  though  sometimes  conglomer-' 
atic,  the  larger  particles  being  at  times  a  fourth  of  an  inch  in 
diameter.  It  carries  from  25  per  cent  to  32  per  cent  P2Os.  The 
phosphatic  nature  is  ascribed  to  organic  matter — shells,  bones,  and 
the  droppings  of  marine  animals. 

Within  a  few  years  certain  portions  of  strata  of  Carboniferous 
rocks — mainly  limestones — in  northern  Utah,  southeastern  Idaho, 
and  adjoining  portions  of  Wyoming,  and  in  northern  Nevada,  have 
been  found  surprisingly  rich  in  phosphate.  The  entire  phosphatic 
series,  which  in  places  is  90  feet  in  thickness,  consists  of  alternating 
layers  of  black  or  brown  phosphatic  materials,  shale,  and  hard  blue 
or  gray  compact  limestone.  The  beds  themselves  vary  from  a  few 
inches  to  10  feet  in  thickness,  but  in  the  latter  cases,  are  usually 
broken  by  lean,  shaley  layers.  At  the  base,  the  series  begins  with 
limestone,  which  is  succeeded  by  6  to  8  inches  of  soft  brown  shales. 
Overlying  this  is  the  main  phosphate  bed,  5  to  6  feet  in  thickness. 
This  is  oolitic  in  structure,  and  runs  high  in  PaOo.  Several  other 
beds,  from  a  few  inches  to  10  feet  in  thickness,  separated  by  thin 
beds  of  limestone  or  shale,  occur.  The  series  is  overlaid  by  a  coarse- 
grained, locally  brecciated  limestone,  and  above  this  again,  white 
limestone,  red  sandstone,  and  shales,  and  still  again,  other  limestones 
of  blue-gray  and  greenish  colors.  Beneath  are  found  red,  white,, 
and  greenish  quartzites  and  sandstones.  The  strata  have  all  been 
uplifted,  and  sharply  folded  and  faulted.  A  typical  section  is  shown 
in  Fig.  44.  The  material  as  thus  far  shipped  runs  a  little  over  31 


288 


THE  NON-METALLIC  MINERALS. 


per  cent  of  P2O5,  which  is  equivalent  to  70  per  cent  of  bone  phos- 
phate.1 


$^S*         ^:;'^« 


FIG.  44. — Typical  Section  of  Lower  Portion  of  Phosphate  Series,  Montpelier,  Idaho. 
[U.  S.  Geological  Survey.] 

England. — Deposits  of  phosphates  sufficiently  concentrated  for 
commercial  purposes  lie  near  the  upper  limit  of  Cambro-Silurian 
strata  in  North  Wales.  According  to  Davies,  the  material  occurs 
in  the  form  of  nodular  concretions  of  a  size  varying  from  that  of 
an  egg  to  a  cocoanut,  closely  packed  together  and  cemented  by  a 
black  slaty  matrix.  The  concretions  have  often  a  black,  highly 
polished  appearance,  due  to  the  presence  of  graphite,  but  owing  to 

1  F.  B.  Weeks,  Bulletin  No.  315,  U.  S.  Geological  Survey,  1906,  p.  449. 


PHOSPHATES.  289 

the  presence  of  oxidizing  pyrite  they  sometimes  become  rusty  brown. 
The  concretions  carry  from  60  to  69  per  cent  of  phosphate  of  lime; 
the  matrix  is  also  phosphatic.  The  beds  are  highly  tilted  and  are 
overlaid  by  gray  shales  with  fossilized  echinoderms  and  underlaid 
by  dark  crystalline  limestone,  which  also  contains  from  15  to  20  per 
cent  of  phosphatic  material.  Davies  regards  the  deposit  as  repre- 
senting an  old  sea  bottom  on  which  the  phosphatic  matter  of  crustacean 
and  molluscan  life  was  precipitated  and  st:red  during  a  long  period; 
certain  marine  plants  may  also  have  contributed  their  share  of  phos- 
phatic matter.  He  thinks  it  also  possible  that,  as  in  the  Lauren tian 
deposits,  the  water  of  the  sea  may  have  contained  phosphatic  matter 
in  solution  to  be  deposited  independently  of  organic  agencies. 

These  phosphated  beds  have  been  mined  at  Berwin,  where  an 
average  production  over  a  space  of  360  fathoms  was  2  tons  10 
hundredweight  of  phosphate  per  fathom,  of  an  average  strength  of 
46  per  cent.  The  nodules  averaged  from  45  to  55  per  cent  of  phcs- 
phate  of  lime. 

Amorphous  nodular  phosphates  alsD  occur  in  both  the  Upper 
and  Lower  Greensands  of  the  Cretaceous  and  in  Tertiary  deposits. 
Those  of  the  upper  beds  have  been  mined  in  Cambridgeshire  and 
Bedfordshire.  The  phosphatic  material  occurs  in  the  form  of 
shell  casts,  fossils,  and  nodules,  of  a  black  or  dark-brown  color,  of 
varying  hardness,  embedded  in  a  sand  consisting  of  siliceous  and 
calcareous  matter  as  well  as  phosphatic  and  glauconitic  grains. 
The  average  composition  shows  from  40  to  50  per  cent  of  phosphate 
of  lime.  The  thickness  of  the  nodule-bearing  bed  is  rarely  over  a 
foot.  The  nodules  of  the  Lower  Greensands  differ  from  those  of 
the  Upper  in  many  details,  the  more  important  being  their  lower 
percentages  of  phosphate  of  lime  (from  40  to  50  per  cent).  They 
occur  in  a  bed  of  siliceous  sand  which  itself  is  not  phosphatic.  The 
Tertiary  phosphates  reach  their  best  development  in  the  county 
of  Suffolk,  where  they  are  found  at  the  base  of  the  Coralline  and 
Red  Crag  groups  and  immediately  overlying  the  London  clays. 
The  beds  consist  of  a  "mass  of  phosphatic  nodules  and  shell  casts, 
siliceous  pebbles,  teeth  of  cetaceans  and  sharks,  and  many  mammal 
bones,  besides  occasional  fragments  of  Lower  Greensand  chert, 
granite,  and  chalk  flints."  The  nodules  vary  in  both  quality  and 
quantity.  They  are  at  times  of  a  compact  and  brittle  nature,  while 


290  THE  NON-METALLIC  MINERALS. 

at  others  they  are  tough  and  siliceous.     They  average  about  53 
per  cent  phosphate  of  lime  and  13  per  cent  phosphate  of  iron. 

France. — Phosphates  of  the  nodular  type  occur  .in  beds  of  Cre- 
taceous age  in  the  provinces  of  Ardennes  and  Meuse,  and  to  a  less 
extent  in  others  in  Northern  France;  in  the  department  of  Cote-d'Or, 
and  along  the  Rhone  at  Bellegarde,  Seyssel,  and  Grenoble.  As 
in  England,  the  phosphatic  nodules  of  the  northern  area,  such  as 
are  of  commercial  importance,  occur  in  both  the  Upper  and  Lower 
Greensands.  They  resemble  in  a  general  way  the  English  phos- 
phates, but  are  described  as  soft  and  porous  and  easily  disintegrat- 
ing when  exposed  to  the  air.  Those  of  the  Upper  Greensand  average 
some  55  per  cent  of  phosphate  of  lime. 

More  recently  deposits  have  been  described  by  M.  J.  Gosselet,* 
near  Fresnoy-le- Grand,  in  the  north  of  France.  The  phosphatic 
material  occurs  in  a  zone  of  gray  chalk  some  6  feet  in  thickness 
(i  J  to  2  meters),  and  is  in  the  form  of  concretionary  nodules  forming 
a  sort  of  conglomerate  in  the  lower  part  of  the  bed.  A  portion 
of  the  chalk  is  also  phosphatic.  Phosphatic  material  (of  the  type 
of  phosphorites)  is  found  in  fissures  and  pockets  in  the  upper  portion 
of  limestones  of  Middle  Jurassic  (Oxfordian)  age,  in  the  depart- 
ments of  Tarn-et- Garonne,  Aveyron,  and  Zoti. 

The  deposits  are  of  two  kinds.  The  first  occurring  in  irregular 
cavities  or  pockets  never  over  a  few  yards  long,  and  the  second  in 
the  form  of  elongated  leads  with  the  sides  nearly  vertical.  These 
are  generally  shallow,  and  thin  out  very  rapidly  at  a  short  distance 
below  the  surface. 

The  nodules  or  concretions  are  of  a  white  or  gray  color,  waxy 
luster,  and  opal-like  appearance,  and  occur  in  the  form  of  tubercular 
or  kidney-shaped  masses  embedded  in  ferruginous  clay  in  the  clefts 
of  the  limestone,  or  in  geodic,  fibrous,  and  radiating  forms. 

The  material  of  this  region  is  known  commercially  as  Bordeaux 
phosphate,  being  shipped  mainly  from  Bordeaux.  It  averages  from 
70  to  75  per  cent  phosphate  of  lime,  the  impurities  being  mainly  iron 
oxides  and  siliceous  matter. 

1  Annales  de  la  SocietC  Geologique  du  Nord,  XXI,  1895,  p.  149. 


PHOSPHATES.  291 

Gautier l  describes  deposits  of  phosphates  estimated  to  the 
amount  of  120,000  to  300,000  tons  on  the  floors  of  the  Grotte  de 
Minerve,  near  the  village  of  Mmerve  on  the  northeast  flank  of  the 
Pyrenees,  in  Aude,  France.  The  cave  proper  is  in  nummulitic 
limestone  of  Eocene  age,  the  floors  being  formed  by  Devonian 
rocks.  The  filling  material  consists  of  cave  earth  and  bone  breccia 
below  which  are  the  aggregates  of  concretionary  phosphorites  and 
other  phosphatic  compounds  of  lime  and  alumina,  the  more  in- 
teresting being  Brushite,  a  hydrous  tribasic  calcium  phosphate 
hitherto  known  only  as  a  secondary  incrustation  on  guano  from  the 
West  India  Islands,  and  Mineruite,  a  new  species  having  the  formula 
A12O3.P2O5,7H2O,  a  hydrous  aluminum  phosphate,  existing  in  the 
form  of  a  white  plastic  clay-like  mass  filling  a  vein  from  a  few  inches 
to  2  or  more  feet  in  thickness. 

Germany. — According  to  Davies,  the  principal  phosphate  regions 
of  North  Germany  occupy  an  irregular  area  bounded  on  the  north- 
east by  the  town  of  Weilburg,  on  the  northwest  by  the  Westerwald, 
on  the  east  by  the  Taunus  Mountains,  and  on  the  south  by  the  town 
of  Dietz.  The  material  occurs  in  the  form  of  irregular  nodular 
masses  of  all  sizes  up  to  those  of  several  tons  weight,  embedded 
in  clay  which  rests  upon  Devonian  limestone  and  is  overlaid  by 
another  stratum  of  clay.  The  phosphate-bearing  clay  varies  in 
thickness  from  6  inches  to  10  feet.  With  the  phosphate  nodules 
are  not  infrequently  associated  deposits  of  manganese  and  hematite. 
Davies  regards  the  deposits  as  of  early  Tertiary  age.  The  color 
of  the  freshly  mined  material  varies  from  pale  buff  to  dark  brown, 
varying  in  specific  gravity  from  1.9  to  2.8,  the  quality  deteriorating 
with  the  increase  in  gravity.  Selected  samples  of  the  staple  nodules 
yielded  as  high  as  92  per  cent  phosphate  of  lime;  but  the  average 
is  much  low^r,  being  but  about  50  to  60  per  cent  phosphate  of 
lime. 

Belgium. — Nodular  phosphates  belonging  to  the  Upper  Cre- 
taceous formations  occur  in  the  province  of  Hainaut,  where  t':ey 
form  the  basis  of  an  extensive  industry.  7  he  nodules  which  are 

1  Annales  des  Mines,  V,  p.  5. 


292  THE  NON-METALLIC  MINERALS. 

generally  of  a  brown  color  and  vary  in  size  from  the  fraction  of  i  to 
4  or  5  inches  in  diameter,  lie  in  a  coarse-grained,  friable  rock  called 
the  brown  or  gray  chalk,  which  itself  immediately  underlies  what  is 
known  as  the  Ciply  conglomerate.  The  phosphate-bearing  bed  is 
sometimes  nearly  100  feet  in  thickness,  but  is.  richest  in  the  upper 
10  feet,  where  it  is  estimated  the  phosphatic  pebbles  constitute 
some  75  per  cent  of  its  bulk.  Below  this  the  bed  grows  gradually 
poorer,  passing  by  gradations  into  the  white  chalk  below. 

The  overlying  conglomerate  also  carries  phosphate  nodules, 
which  carry  from  25  to  50  per  cent  phosphate  of  lime.  Owing 
to  the  hardness  of  the  inclosing  rock  they  are  less  mined  than  those 
in  the  beds  'beneath.  The  mining  of  phosphates  is  carried  on  ex- 
tensively near  the  town  of  Mons,  on  the  lands  of  the  communes  of 
Cuesmes,  Ciply,  Mesvin,  Nouvelles,  Spiennes,  St.  Symphorien,  and 
Hyon.  The  annual  output  has  gradually  increased  from  between 
3,000  and  4,000  tons  in  1887  to  85,000  tons  in  1894,  Other  phos- 
phatic deposits  are  described  l  as  occurring  in  the  provinces  of 
Antwerp  and  Liege. 

Italy. — Phosphatic  deposits  consisting  of  coprolites,  bones,  etc., 
embedded  in  a  porous  Tertiary  limestone,  occur  between  Gallipoli 
and  Otranto,  Cape  Leuca,  west  of  the  Gulf  of  Taranto,  on  the 
Italian  coast.  There  are  two  beds  having  a  thickness  of  19 J  and 
31 J  inches,  respectively,  and  which  have  been  traced  for  a  distance 
of  some  160  yards.  Analyses  show  them  to  be  of  low  grade,  rarely 
carrying  as  high  as  10  per  cent  P2O5. 

Tunis. — Phosphatic  nodules  in  the  form  of  cylindrical  coprolites 
and  clustered  aggregates  have  been  found  in  Tertiary  strata  covering 
considerable  areas  in  the  region  south  of  Tunis.  The  coprolite 
nodules  are  stated  to  carry  as  high  as  70  per  cent  of  calcium  phos- 
phate, and  the  clustered  aggregate  some  52  per  cent. 

Russia. — Rich  phosphate  deposits  of  Cretaceous  age  occur  in  the 
governments  of  Smolensk,  Orlow,  Koursk,  and  Vorouez,  between  the 
rivers  Dnieper  and  the  Don  in  European  Russia.  The  deposits  lie 
mostly  in  a  sandy  marl,  underlying  white  chalk  and  overlying  green- 

1  Annales  de  la  Societ£  Geologique  de  Belgique,  XVIII,  1890,  p.  185. 


PHOSPHATES.  293 

sands,  which  also  carry  beds  of  from  6  to  1 2  inches  thickness  of  phos- 
phatic  nodules.  The  nodules  are  dark,  often  nearly  black  in  color, 
and  are  intermixed  with  gray,  brown,  and  yellow  sands.  The  depth 
of  the  beds  below  the  surface  is  variable.  Yermolow  *  divides  the 
deposits  into  two  groups,  the  first  presenting  the  form  of  separate 
nodules,  rounded  or  kidney-shaped,  of  variable  size,  and  black, 
brown,  gray,  or  green  in  color.  The  second  is  in  form  of  an  agglom- 
eration of  large  nodules  cemented  together  into  a  sort  of  flag,  which 
used  to  be  quarried  for  road  purposes.  The  nodules  in  this  ag- 
glomerate are  richer  in  phosphoric  acid  wrhen  most  dense  and  of  a 
deep-black  color,  the  sandy  varieties  being  comparatively  poor.  The 
cement  carrying  the  nodules  contains  numerous  fossil  bones,  shells, 
corals,  etc.,  which  are  also  phosphatic.  The  samples  yield  about 
30  to  60  per  cent  phosphate  of  lime.  Other  deposits  occur  south 
of  Saratov,  on  the  Volga ;  at  Tambov  and  Spask,  where  the  overlying 
rock  is  a  greensand  in  place  of  the  chalk;  north  of  Moscow;  east  of 
Nijni  Novgorod;  at  Kiev,  on  the  Dnieper;  Kamenetz,  Podolsk,  on 
the  Dniester,  .and  at  Grodno,  on  the  Niemen. 

Maltese  Islands.2 — Nodular  phosphates  occur  in  Miocene  beds 
on  the  islands  of  Malta,  Gozo,  and  Comino,  of  the  Maltese  group 
in  the  Mediterranean  Sea.  The  bed  containing  the  nodules  is  in 
what  is  known  as  the  Globigerina  limestone,  which  underlies  an 
upper  coralline  limestone,  greensands,  and  blue  clays,  and  overlies 
the  lower  coralline  limestone.  Upper  and  lower  beds  all  carry 
phosphoric  acid  in  small  amounts.  There  are  four  seams  of  nodules, 
the  first  varying  in  different  localities  from  9  to  15  inches  in  thickness. 
The  second  is  more  constant  in  character,  averaging  some  2  feet 
in  thickness  and  consisting  of  an  aggregate  of  irregularly  shaped 
nodules,  intermixed  with  which  are  considerable  quantities  of  the 
phosphatized  remains  of  mollusks,  corallines,  echinoderms,  crus- 
taceans, sharks,  whales,  etc.,  the  whole  being  firmly  bound  together 
by  an  interstitial  cement,  composed  of  foraminiferal  and  other 
calcareous  matter  similar  to  that  of  which  the  overlying  beds  are 
made  up.  The  third  seam  is  the  poorest  of  the  lot  and  consists 

1  Recherches  sur  les  Gisements  de  Phosphate  de  Chaux  Fossil  en  Russie. 

2  J.  H.  Cooke,  The  Phosphate  Beds  of  the  Maltese  Islands.     Engineering  and  Min- 
ing Journal,  LIV,  1892,  p.  200. 


294 


THE  NON-METALLIC  MINERALS. 


of  two  or  more  thin  layers  of  nodules,  none  of  which  exceeds  3  inches 
in  thickness.  Between  this  and  the  fourth  and  lowest  seam,  which 
is  the  most  important  of  all,  is  a  bed  of  rock  some  50  to  80  feet  in 
thickness.  The  seam  averages  some  3}  feet  in  thickness.  The 
nodules  are  of  a  dark-chocolate  color  embedded  in  a  calcareous 
matrix,  from  which  they  are  freed  by  calcination.  The  composi- 
tion of  I,  the  nodules,  and  II,  the  average  composition  of  nodules 
and  interstitial  cement,  is  given  below,  from  analyses  by  Drs.  Murray 
and  Blake: 


Constituents. 

I. 

II. 

Sulphate  of  lime 

2.26 

47.14 
38-34 
5-98 
Trace. 
6.08 

1.97 
51.12 
31.66 
10.59 

?3-83 
60.87 

Carbonate  of  lime 

Phosphate  of  lime 

Alumina  (Al  O3) 

Oxide  of  iron  (Fe  CX) 

Residue  

Total.  . 

99.80 

IOO.OO 

a.  Silica.  b.  Moisture. 

Guano,  soluble  and  leached. — The  largest  and  best-known 
deposits  of  unleached  guanos  are  found  on  the  mainland  and  small 
islands  off  the  coasts  of  Peru  and  Bolivia,  where  abundant  animal 
life  and  lack  of  rainfall  have  contributed  to  their  formation  and 
preservation.  These  deposits  consist  mainly  of  the  evacuations 
of  sea  fowl  and  marine  animals,  such  as  flamingoes,  divers,  pen- 
guins, and  sea  lions.  Mixed  with  them  is  naturally  more  or  less 
bone  and  animal  matter  furnished  by  the  dead  bodies  of  both  birds 
and  mammals.  The  deposits  vary  indefinitely  in  extent  and  thick- 
ness, but  have  attained  in  places  a  depth  of  upward  of  100  feet. 
As  a  rule  they  are  more  compact  beneath  than  at  the  surface,  but 
may  be  readily  removed  by  pick  and  shovel.  The  first  deposits  to 
be  worked  are  stated  to  have  been  those  of  the  Chincha  Islands,  off 
the  Peruvian  coast.  These  were  practically  exhausted  as  early  as 
1872.  Other  islands  which  have  been  worked  and  completely 
if  not  entirely  stripped  are  those  of  Macabi,  Guafiape,  Ballestas, 
Lobos,  Foca,  Pabellon  de  Pica,  Tortuga,  and  Huanillos. 

A  mean  of  21  analyses  of  Macabi  Island  guano,  by  Barral,  as 
quoted  by  Penrose,1  showed: 

1  Bulletin  No.  46  of  the  United  States  Geological  Survey. 


PHOSPHATES. 


295 


Nitrogen 10.90 

Phosphates 27.60 

Potash 2  to  3 

Other  analyses  are  given  in  the  following  table: 


Constituents. 

Angamos,  Coast 
of  Bolivia, 
White  Guano. 

Bolivian. 

Los 
Patos. 

Island  of 
Elide,  Coast  of 
California. 

Organic  matter  

70.21  to  52.92 
20.09  "   !4-38 
24.36  "   17.44 
13.30  "  20.95 

23.00 

3.38 
4.10 
48.60 

32-45 
5-92 
7.l8 
34.81 

27-37  to  34-50 
1.34"     6.98 
1.62  "     8.46 
028.00  "  31.00 

Containing  nitrogen 

Equivalent  in  ammonia.  .  . 
Total  phosphates  

Constituents. 

Ilot  de  Pe- 
dro-Bey, 
Coast 
of  Cuba. 

Mexican 
Coast. 

Galapa- 
gos, 
Ecuador. 

Falkland 
Islands. 

Organic  matter. 

6.16 

0.28 

°-34 
48.52 

13.05  to  18.00 

0.21   "       3.45 
O.26  "       4.19 

8.00  "  25.00 

17.35  to  28.68 
0.56  "      2.26 
0.68"     2.74 
021.46  "  25.62 

Containing  nitrogen. 

0.7 
0.85 
60.30 

Equivalent  in  ammonia.  .  . 
Total  phosphates. 

a.  Containing  sometimes  very  considerable  quantities  of  phosphates  of  alumina  and  the 
oxide  of  iron. 

Aside  from  on  the  islands,  guano  is  found  all  along  the  coast  of 
the  Chilean  province  of  Tarapaca,  from  Carmarones  Bay  to  the 
mouth  of  the  river  Loa,  there  being  scarcely  a  prominence  or  rock 
on  the  shore  that  is  entirely  free  from  it.  According  to  the  Journal 
of  the  Society  of  Chemical  Industry,1  the  deposits  have  been  known 
from  a  very  early  date.  The  aborigines  of  the  valleys  and  gullies 
of  Tarapaca,  Mamma,  Huatacondo,  Camina,  and  Quisma  were 
acquainted  with  the  fertilizing  qualities  of  guano,  and  conveyed  it 
from  the  coast  to  their  farms  on  the  backs  of  llamas. 

The  southern  beds  vary  so  much  in  aspect  and  color  that  it 
frequently  requires  an  experienced  eye  to  make  them  out.  Many 
of  the  deposits  are  covered  with  immense  layers  of  sand,  while 
others  are  buried  beneath  a  solid  layer  of  conglomerate.  Guano 
is  also  frequently  found  in  the  fissures  and  gullies  which  descend 
to  the  seashore.  The  richest  and  largest  beds  are  at  Pabellon  de 
Pica,  Punta  de  Lobos,  Huanillos,  and  Chipana. 


1  Volume  VI,  1887,  p.  228. 


296 


THE  NON-METALLIC  MINERALS. 


Aside  from  the  localities  above  mentioned,  guano  is  found  on  the 
islands  Itschabo,  Possession,  Pamora,  and  Halifax,  off  the  Namagua 
coast  of  South  Africa.  The  material  is  described  as  forming  a 
grayish-brown  powder,  free  from  large  lumps,  and  possessing  a 
faint  ammoniacal  odor.  It  carries  from  8  to  14  per  cent  of  nitrogen 
and  8  to  12  per  cent  of  phosphoric  acid.1 

The  West  India  Islands. — Phosphates  belonging  to  the  class  of 
leached  guanos  occur  in  considerable  abundance  on  several  of  the 
islands  of  the  West  Indies  group,  the  principal  localities  being 
Sombrero,  Navassa,  Turk,  St.  Martin,  Aruba,  Curacao,  Orchillas, 
Arenas,  Roncador,  Swan,  Cat  or  Guanahani,  Redonda,  the  Pedro 
and  Morant  Keys,  and  the  reefs  of  Los  Monges  and  Aves  in  Mara- 
caibo  Gulf.  These,  as  would  naturally  be  expected  from  their 
mode  of  origin,  vary  greatly,  not  merely  in  appearances,  but  in 
chemical  composition  as  well.  That  of  Sombrero  is  described  2 
as  occurring  in  two  forms — one  a  granular,  porous,  and  friable 
mass  of  a  white,  pink,  green,  blue,  or  yellow  color;  the  other  as 
a  dense,  massive,  and  homogeneous  deposit  of  a  white  or  yellow 
color.  Many  bones  occur.  The  phosphate  carries  from  70  to  75 
per  cent  phosphate  of  lime.  An  analysis  as  given  by  Davies  3  is 
as  follows: 

ANALYSIS    OF    SOMBRERO    PHOSPHATE. 


Constituents. 

Per  Cent. 

Moisture  and  water  of  combination  
Phosphoric  acid  4 

8.92 

31    73 

Lime 

AC      6O 

Carbonic  acid** 

5OO 

Oxide  of  iron  and  alumina 

7   O7 

Insoluble  siliceous  matter  . 

o  60 

IOO.OO 

The  Navassa  phosphate  is  described  by  DTnvilliers  6  as  occurring 
(i)  in  the  form  of  a  gray  phosphate  confined  to  the  lower  levels  of 

1  Journal  of  the  Society  of  Chemical  Industry,  I,  1882,  p.  29. 

2  R.  F.  Penrose,  Bulletin  No.  46  of  the  U.  S.  Geological  Society. 

3  D.  C.  Davies,  Earthy  and  Other  Minerals,  p.  178. 

4  Equal  to  tricalcic  phosphate,  69.27  per  cent. 
'  Equal  to  carbonate  of  lime,  13.61  per  cent. 

*  Bulletin  of  the  Geological  Society  of  America,  II,  1891,  p.  75-89. 


PHOSPHATES. 


297 


the  island,  and  (2)  a  red  variety  occupying  the  oval  flat  of  the  in- 
terior. The  gray  is  the  better  variety,  as  shown  by  the  analyses 
below,  though  both  are  aluminous,  and  difficult  of  manipulation 
on  that  account.  Both  varieties  occur  in  cavities  and  fissures  in 
the  surface  of  the  hard  gray,  white,  or  blue  limestone,  of  which  the 
island  is  mainly  composed.  These  cavities  or  pockets  are  rarely 
more  than  4  or  5  yards  wide  on  the  surface,  and  frequently  much 
smaller,  and  of  depths  varying  from  5  to  25  feet.  The  deposits, 
so  far  as  explored,  are  wholly  superficial.  Experimental  shafts 
sunk  to  a  depth  of  250  feet  have  failed  to  bring  to  light  any  deeper 
lying  beds. 


ANALYSIS   OF   GRAY  NAVASSA  PHOSPHATE. 


Constituents. 

Per  Cent. 

Water  at  100°  C 

2     T,  3 

Organic  matter  and  water  of  combination 
Lime     .    .            

7.63 
34    22 

Magnesia  

O    CI 

Sesquioxide  of  iron  and  alumina     

ir    77 

Potash  and  soda                 

0   86 

Phosphoric  acid                      

31    34 

Sulphuric  acid                           

o  28 

Chlorine                                          

O    I< 

Carbonic  acid                      

I    84. 

Silica                              

4r  7 

Total                

OO   4.6 

ANALYSIS  OF  RED  NAVASSA  PHOSPHATE. 


Constituents. 

Per  Cent. 

Loss  on  ignition 

14    223 

Lime 

23    OOO 

Magnesia 

Trace 

Sesquioxide  of  iron                                 .    . 

o  7o6 

Alumina                                   .    

18  42? 

Phosphoric  acid 

20  770 

Sulphuric  acid                   

i   160 

Carbonic  acid  (by  difference)   

•}    r  27 

Total  .           

IOO    O2O 

298 


THE  NON-METALLIC  MINERALS. 


The  Aruba  phosphate  is  described  as  a  hard,  massive  variety 
of  a  white  to  dark-brown  color.  The  underlying  corals  of 
this  island  are  sometimes  found  phosphatized.  An  analysis 
given  by  Da  vies  is  as  follows: 


ANALYSIS   OF  ARUBA  PHOSPHATE. 


Constituents. 

Per  Cent. 

^Moisture              

8.  so 

\Vater  of  combination 

41  e 

Phosphoric  acid  2 

28   4.7 

34    O7 

Maoresia. 

O    4? 

Carbonic  acid  3 

2     3O 

Oxiic  of  iron 

4    40 

Alumina                          .        

0    48 

Sulphuric  acid                   

1.81 

Insoluble  siliceous  matter  

6.28 

Total  

IOO.OO 

The  Pedro  Keys,  Redonda,  and  Alta  Vela  phosphates  carry 
larger  percentages  of  alumina  and  iron  oxides,  necessitating  special 
methods  of  preparation. 

Deposits  of  leached  guano  of  considerable  extent  have  existed 
on  several  islands  of  the  Polynesian  Archipelago,  in  the  Pacific 
Ocean,  the  better  known  being  those  of  Baker,  Rowland,  Jarvis, 
Maiden,  Birmie,  Phoenix,  and  Enderbury  islands.  The  deposits 
are  described  4  as  varying  from  6  inches  to  several  feet  in  thickness, 
of  a  whitish-brown  or  red  color,  pulverulent  when  dry,  sometimes 
in  the  form  of  fine  powder  and  again  in  coarse  grains.  Though 
closely  compacted,  the  material  can,  as  a  rule,  be  readily  removed  by 
pick  and  shovel.  The  purest  varieties  are  those  lying  on  the  un- 
altered coral  limestones,  of  which  the  islands  are  mainly  composed. 
Those  lying  upon  gypsum  have  become  contaminated  with  sulphate 
of  lime.  In  places  the  deposits  are  covered  with  a  thin  crust  due 


2  Equal  to  tricalcic  phosphate,  62.15  per  cent. 

8  Equal  to  carbonate  of  lime,  5.22  per  cent. 

4  J.  D.  Hague,  American  Journal  of  Science,  XXXIV,  1862,  p.  224. 


PHOSPHATES. 


2  99 


to  the  action  of  atmospheric  agencies.  On  Jarvis  Island  a  con- 
siderable share  of  the  deposit  is  covered  by  material  of  this  crust- 
like  character.  Such  on  analysis  are  found  to  contain  less  water 
and  a  corresponding  higher  percentage  of  lime  and  phosphoric 
acid  than  the  loosely  compacted  material,  being,  indeed,  a  nearly 
pure  phosphate  of  lime.  The  following  analyses  show  the 
general  character  of  the  guanos  from  Baker  Island,  No.  I 
being  freshly  deposited  and  consisting  of  the  dung  of  the 
frigate  bird  (Pelicanus  aquilus).  No.  II  is  a  light-colored  variety 
from  a  deep  part  of  the  deposit,  and  No.  Ill  dark  guano  from  a 
shallow  part. 


ANALYSES    OF    GUANO. 


Constituents. 

I. 

II. 

III. 

Moisture  expelled  at  212°  F. 

10  4.0 

2  O2 

I  82 

Loss  by  ignition 

36  88 

8  T.2 

8  so 

Insoluble  in  HC1  (unconsumed  by  ignition) 

o  78 

Lime 

22  4.1 

4.2  74. 

4.2   34. 

^Magnesia 

I  4.6 

2  ^4. 

27? 

Sulphuric  acid 

2   36 

I    3O 

I   24. 

Phosphoric  acid  

21.27 

30  7O 

4O.I4 

Carbonic  acid,  chlorine,  and  alkalies,  undetermined.  . 

4.44 

2.48 

3-21 

Total  

IOO.OO 

IOO.OO 

IOO.OO 

Bat  Guano. — The  dry  atmosphere  of  caves  preserves  indefinitely 
the  fecal  matter  of  bats  and  such  other  animals  as  may  frequent 
them.  Such  under  favorable  conditions  may  accumulate  in  suf- 
ficient quantities  to  become  of  economic  importance,  being  gathered 
and  used  as  a  fertilizer  under  the  name  of  bat  guano.  The  usual 
form  of  the  entrances  to  caves  is,  however,  such  as  to  make  the 
process  of  removal  tedious  and  expensive. 

Bat  guano  is,  as  a  rule,  dark  in  color,  of  a  glossy,  almost  muci- 
laginous appearance,  and  quite  hard.  Its  composition  is  shown 
in  the  following  analysis  of  a  sample  from  the  Wyandotte  caves  * 
in  southern  Indiana: 


1  Geology  of  Indiana,  1878,  p.  163. 


3oo 


THE  NON-METALLIC  MINERALS* 


ANALYSIS  OF  BAT  GUANO. 


Constituents. 

Per  Cent. 

Loss  at  red  heat  

4.4    IO 

Organic  matter  

4OO 

Ammonia 

Silica 

•  ^o 

6     17 

Alumina  

U.  ij 

MT.O 

Ferric  oxide  .... 

I     2O 

Lime  

7    O^ 

Magnesia  

I    I  J 

Sulphuric  acid  

r    21 

Carbonic  acid 

3    77 

Phosphoric  acid 

o-  /  / 
I    21 

Chloride  of  alkalies  and  loss 

<;    82 

IOO.OO 

According  to  the  reports  of  the  State  geologist,  the  caves  in  the 
Silurian  strata  in  Burnet  County,  Texas,  are  in  many  instances 
enormously  rich  in  bat  guano. 

Muntz  and  Marcano  *  have  called  attention  to  the  extensive 
deposits  of  guano,  sometimes  amounting  to  millions  of  tons,  in 
caves  in  Venezuela  and  other  parts  of  South  America. 

According  to  them  the  deposits  consist  not  merely  of  the  excreta 
of  the  birds  and  bats  which  frequent  the  caves,  but  also  of  the  dead 
bodies  of  these  and  other  animals.  The  excreta  were  found  to 
consist  almost  wholly  of  the  remains  of  insects.  Through  the 
agency  of  bacteria,  nitrification  takes  place,  whereby  the  organic 
nitrogen  is  converted  into  nitric  acid,  which  combines  with  the  lime 
from  the  bones  or  the  carbonate  of  lime  in  the  soils  to  form  nitrates, 
as  described  on  page  319. 

Uses. — The  phosphates  of  the  classes  thus  far  described  are 
used  wholly  for  fertilizer  purposes.  In  their  natural  condition  they 
exist  in  the  form  known  to  chemists  as  tribasic  phosphates — that 
is,  a  compound  in  which  three  atoms  of  a  base  mineral,  usually 
calcium,  are  combined  with  one  of  phosphoric  anhydride  (P2Oa). 
Thus  the  common  tribasic  phosphate  of  lime,  or  tricalcic  phosphate 


1  Comptes  Rendus  de  1'Academie  des  Sciences,  Paris,  1885,  p.  65. 


PHOSPHATES.  301 


as  it  is  more  commonly  termed,  has,  the  formula  C 
parts  by  weight  P2Os  and  54.19,  CaO.  Other  bases,  as  alumina, 
iron,  or  magnesia,  may  partially  replace  the  lime,  but  the  phos- 
phate is  always  deteriorated  thereby.  This  is  particularly  the 
case  when  aluminum  and  iron  are  the  replacing  constituents.  Al- 
though when  finely  ground  the  tricalcic  phosphates  are  of  possible 
value  for  fertilizers,  it  is  customary  to  first  submit  them  to  chemical 
treatment  in  order  to  render  them  more  readily  soluble. 

This  treatment  consists,  as  a  rule,  in  converting  them  into  a 
superphosphate  by  sulphuric  acid,  whereby  a  portion  of  the  bases 
become  converted  into  sulphates  and  the  anhydrous  and  insoluble 
tribasic  phosphate  into  a  hydrous  and  soluble  monobasic  form  of 
the  formula  CaO.(H2O)2.P2O5.  There  are  other  reactions  than 
that  above  given,  the  discussion  of  which  would  be  out  of  place 
here,  and  the  reader  is  referred  to  especial  treatises  on  the  subject. 

BIBLIOGRAPHY. 

R.  A.  F.  PENROSE,  JR.     Nature  and  Origin  of  Deposits  of  Phosphate  of  Lime.     Bul- 
letin No.  46,  U.  S.  Geological  Survey,  1888.      Gives  a  bibliography,  up  to  date 
of  publication.     The  following  have  appeared  since: 
W.  H.  ADAMS.     List  of  Commercial  Phosphates. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XVIII,   1889, 
p.  649. 

PAUL  LEVY.  Des  phosphates  de  chaux.  De  leurs  principaux  gisements  en  France 
et  a  1'etranger  des  gisements  recemment  decouvertes.  Utilisation  en  agriculture; 
assimilation  par  les  plants. 

Annales  des  Sciences  Geologique,  XX,  1889,  P-  7&- 

THEODOR  DELMAR.  Das  Phosphoritlager  von  Steinbach  und  allgemeine  Gesichts- 
punkte  iiber  Phosphorite. 

Vierteljahrschrift  der  Naturforschenden  Gesellschaft  in  Zurich,  1890,  p.  182. 
HENRI  LASNE.     Sur  les  Terrains  phosphates  des  environs  de  Doullens.     Etage  Seno- 
nien  et  Terrains  superposes. 

Bulletin  de  la  Societe  Geologique  de  France,  XVIII,  1890,  p.  441. 
Idem,  XX,  1892,  p.  211. 
Idem,  XXII,  1894,  p.  345. 

HJALMAR  LUNDBOHM.  Apatitforekomster  I  Gellivare  Malmberg  och  Kringliggande 
Trakt. 

Sveriges  Geologiska  Undersokning,  ser.  C,  1890,  p.  48. 
X.  STAINIER.     Les  depots  phosphates  des  environs  de  Thuillies. 

Annales  de  la  Societe  Geologique  Belgique,  XVII,  1890,  p.  LXVL 
X.  STAINIER.     Les  Phosphorites  du  Portugal. 
Idem,  p.  223. 


302  THE  NON-METALLIC   MINERALS. 

EDWARD  V  D'!NVILLIERS.     Phosphate  Deposits  of  the  Island  of  Navassa. 

Bulletin  of  the  Geological  Society  of  America,  II,  1891,  p.  75. 
N.  DE  MARCY.     Remarques  sur  les  Gites  de  Phosphate  de  Chaux  de  la  Picardie. 

Bulletin  de  la  Societe  Geologique  de  France,  XIX,  1891,  p.  854. 
EUGENE  A.  SMITH.     Phosphates  and  Marls  of  Alabama. 

Bulletin  No.  2,  Geological  Survey  of  Alabama,  1892. 
JOHN  H.  COOKE.     The  Phosphate  Beds  of  the  Maltese  Islands. 

Engineering  and  Mining  Journal,  LIV,  1892,  p.  200. 
D.  C.  DAVIES.     Phosphate  of  Lime. 

Chaps.  VII,  VIII,  IX,  X,  pp.  109-180,  of  A  Treatise  on  Earthy  and  Other 
Minerals  and  Mining,  3d  ed.,  revised  by  E.  Henry  Da  vies.     London:    Crosby, 
Lockwood  &  Son,  1892. 
HJALMAR  LUNDBOHM.     Apatitforekomster  I  Norrbottens  Malmberg. 

Sveriges  Geologiska  Undersokung,  ser.  C,  1892,  p.  38. 

N.  A.  PRATT.     Florida  Phosphates;    The  Origin  of  the  Boulder  Phosphates  of  the 
Withlacoochee  River  District. 

Engineering  and  Mining  Journal,  LIII,  1892,  p.  380. 
FRANCIS  WYATT.     Phosphates  of  America. 

New  York,  4th  ed.,  1892. 

W.  P.   BLAKE.     Contribution  to  the  Early  Historv  of  the  Industry  of  Phosphate  of 
Lime  in  the  United  States. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXI,  1893,  P-  I57» 
A,  GAUTIER.     Sur  des  phosphates  en  roche  d'origine  animale  et  sur  un  nouveau  de 
phosphorites. 

Comptes  Rendus,  CXVI,  1893,  pp.  928  and  1022. 

Sur    la    genese  des   phosphates    naturels,  et  en  particulier   de  ceux  qui  ont 

emprunte  leur  phosphore  aux  etres  organises. 
Comptes  Rendus,  CXVI,  1893,  p.  1271. 

J.  GOSSELET.     Note  sur  les  gites  du  Phosphate  de  Chaux  de  Templeux-Bellicourt  et 
de  Buire. 

Societe  Geologique  du  Nord,  XXI,  1893,  p.  2. 

Note  sur  les  gites  de  Phosphate  de  Chaux  des  environs  de  Fresnoy-le-Grand. 

Idem,  p.  149. 
GEO.  H.  ELDRIDGE.     A  Preliminary  Sketch  of  the  Phosphates  of  Florida.      % 

Transactions  of  the  American  Institute  Mining  Engineers,  XXI,  1893,  P-  T9^' 
CHARLES  HELSON.     Notes  sur  la  nature  et  le  gisement  du  phosphate  de  chaux  naturel 
dans  les  departments  du  Tarn-et-Garonne  et  du  Tarn. 

Societe  Geologique  du  Nord,  XXI,  1893,  p.  246. 

WALTER  B.  M.  DAVIDSON.     Notes  on  the  Geological  Origin  of  Phosphate  of  Lime 
in  the  United  States  and  Canada. 

Transactions  of  the  American  Institute  Mining  Engineers,  XXI,  1893,  P-  r39* 
WILLIAM  B.  PHILLIPS.     A  List  of  Minerals  containing  at  least  one  per  cent  of  Phos- 
phoric Acid. 

Transactions  of  the  American  Institute  Mining  Engineers,  XXI,  1893,  p.  188. 
H.  B.  SMALL.     The  Phosphate  Mines  of  Canada. 

Transactions  of  the  American  Institute  Mining  Engineers,  XXI,  1893,  p.  774. 
JOHN  STEWART.     Laurentian  Low-grade  Phosphate  Ores. 

Transactions  of  the  American  Institute  Mining  Engineers,  XXI,  1893,  p.  176. 


PHOSPHATES  303 

The  Phosphate  Industry  of  the  United  States. 

Sixth  Special  Report  of  the  Commissioner  of  Labor,  1893.     Washington:   Gov- 
ernment Printing  Office.   . 

M.  BLAYAC.     Description  Geologique  de  la  Region  des  Phosphates  du  dyr  et  du 
Kouif  Pres  Tebessa. 

Annales  des  Mines,  VI,  1894,  p.  319. 

Note  sur  les  Lambeaux  Suessoniens  a  Phosphate  de  Chaux  de  Bordj  Redir 

et  du  Djebel  Mzeita. 

Idem,  p.  331. 
EUGENE  A.  SMITH.     The  Phosphates  and  Marls  of  the  State. 

Report  on  the  Geology  of  the  Coastal  Plain  of  Alabama,  1894,  pp.  449-525. 
A.  GAUTIER.     Sur  un  Gisement  de  Phosphates  de  Chaux  et  d'Alumine  contenant  des 
especes  rares  ou  nouvelles  et  sur  la  Genese  des  Phosphates  et  Nitres  naturels. 

Annales  des  Mines,  V,  1894,  p.  5. 
DAVID  LEVAT.     Etude,  sur  1'industrie  des  Phosphates  et  Superphosphates. 

Annales  des  Mines,  VII,  1895,  P-  I35- 
J.  M.  SAFFORD.     Tennessee  Phosphate  Rocks. 

Reportof  the  Commissioner  of  Agriculture,  Nashville,  Tennessee,   1895,  P-  I^- 
CHARLES  WILLARD  HAYES.     The  Tennessee  Phosphates. 

Extract  from  the  Seventeenth  Annual  Report  of  the  U.  S.  Geological  Survey, 
1895-96.     Pt.  2,  Economic  Geology  and  Hydrography.     Washington:    Govern- 
ment Printing  Office,  1896.     Also  Twenty-first  Annual  Report,  J  art  III,  1899- 
1900. 
M.  BADOUSEAU.     Sur  les  gisements  de  chaux  phosphates  de  1'Estremadure. 

Bulletin  de  la  Societe  Centrale  Agriculture  de  France,  XXXVIII. 
X.  STAINER.     Bibliographie  Gen  era  le  des  Gisements  des  Phosphates. 

Annales  des  Mines  de  Belgique,  VII,  1902  et  seq. 
L.  P.  BROWN.     The  Phosphate  Deposits  of  the  Southern  States. 

Proceedings  of  the  Engineering  Association  of  the  South.     XV,  No.  2,  1904, 
pp.  53-128. 
F.  B.  WEEKS.     Bulletin  No.  315,  U.  S.  Geological  Survey,  1906. 


2.   MONAZITE. 

Composition,  a  phosphate  of  the  cerium  metals  of  the  general 
formula  (Ce,  La,  Di)  PO.4.  Actual  analyses  as  given  by  Dana 
yielded  results  as  shown  in  table  on  page  304. 

Hardness,  5  to  5.5;  specific  gravity,  4.9  to  5.3.  Color,  hyacinth- 
red  to  brown  and  yellowish,  sub  transparent  to  translucent. 

Localities  and  mode  of  occurrence. — The  common  mode  of  oc- 
currence of  the  mineral  is  that  of  minute  crystals  or  crystalline 
granules  disseminated  throughout  the  mass  of  gneissoid  rocks. 
Owing  to  their  small  size  they  have  been  very  generally  overlooked, 


304 


THE  NON-METALLIC  MINERALS. 


Constituents. 

I. 

II. 

Phosphoric  anhydride  (P  0=) 

20.28 

27  cc 

Cerium  sesquioxide  (Ce  O.). 

71.28 

2Q  2O 

Lanthanum  sesquioxide  (La2O3)  
Didvmium  sesquioxide  (Di  O,).  . 

3*-3° 

\  30-88 

26.26 

2.82 

Iron  sesquioxide  (Fe  O  ) 

I.I* 

Silica  (SiO  ) 

1.40 

1.86 

Thoria  (ThO  ) 

6.40 

Q.^7 

Lime  (CaO)              

O  60 

Ignition                        .    

O.2O 

O  ^2 

Total   - 

00.62 

IOO.6O 

I.  Burke  County,  North  Carolina. 


II.  Arendal,  Norway. 


and  it  is  only  where,  through  the  decomposition  of  the  inclosing 
rock  and  the  concentration  of  the  monazite  and  the  accompanying 
heavy  minerals — as  magnetite,  garnet,  etc. — in  the  form  of  sand, 
that  it  becomes  sufficiently  conspicuous  to  be  evident.  Prof.  O.  A. 
Derby  was  the  first  to  point  out  the  widespread  occurrence  of  the 
mineral  as  a  rock  constituent,  having  obtained  it  in  numerous  and 
hitherto  unsuspected  localities  by  washing  the  debris  from  decom- 
posed gneisses  of  Brazil.  Although  widespread  as  a  rock  constituent 
and  of  interest  from  a  mineralogical  and  petrographical  standpoint 
only  the  localities  mentioned  below  have  thus  far  yielded  the  mineral 
in  commercial  quantities. 

The  Carolinas. — The  mineral  is  found  in  commercial  quantities 
in  the  form  of  small  brownish  or  yellow-brown  water-worn  granules 
in  stream  beds  and  placer  deposits  of  the  Carolinas  throughout  the 
area  shown  in  the  accompanying  map  (Fig.  45).  The  principal 
producing  areas  include  between  1,600  and  2,000  square  miles  in 
Burke,  McDowell,  Rutherford,  Cleveland,  and  Polk  counties,  North 
Carolina,  and  the  northern  part  of  Spartanburg  County,  South 
Carolina.  The  better  deposits  are  found  along  the  waters  of  Silver, 
South  Muddy,  and  North  Muddy  creeks,  and  Henry's  and  Jacob's 
Forks  of  the  Catawba  River  in  DcMowell  and  Burke  counties;  the 
Second  Broad  River  in  McDowell  and  Rutherford  counties;  and 
the  First  Broad  River  in  Rutherford  and  Cleveland  counties,  North 
Carolina,  and  Spartanburg  County,  South  Carolina.  These  streams 
have  their  sources  in  the  South  Mountains,  an  eastern  outlier  of 


s. 


Six 


r-  c    • 

C/3    £ 


PHOSPHATES. 


3°5 


the  Blue  Ridge.  The  country  rock  is  granitic  biotite  gneiss  and 
dioritic  hornblende  gneiss,  intersected  nearly  at  right  angles  to  the 
schistosity  by  a  parallel  system  of  small  auriferous  quartz  veins, 
striking  about  N.  70°  E.  and  dipping  steeply  to  the  N.  W.  The 
thickness  of  the  gravel  deposits  is  from  i  to  2  feet,  and  the  width  of  the 
mountain  streams  in  which  they  occur  is  seldom  over  12  feet.  The 
percentage  of  monazite  in  the  original  sand  varies  from  an  infinites- 


Scale  of  Miles 


0  50  100  160  200 

FIG.  45. — Map  of  monazite  areas  in  the  Carolinas. 
[After  J.  H.  Pratt,  Transactions  of  the  American  Institute  of  Mining  Engineers.] 


imal  quantity  up  to  i  or  2  per  cent.  The  deposits  are  naturally 
richer  near  the  headwaters  of  the  streams. 

From  these  deposits  amounts  varying  from  30,000  pounds  to 
1,573,000  pounds  have  been  washed  annually  since  systematic 
mining  began  in  1893.  In  1901  the  amount  was  748,736  pounds, 
valued  at  $59,262.  The  miner  usually  receives  from  3J  to  5  cents 
per  pound.  The  existence  of  monazite  in  commercial  quantities 
in  this  region  was  first  demonstrated  by  W.  E.  Hidden  in  1879. 

According  to  Lindgren  1  monazite  sand  occurs  in  considerable 
quantities  in  the  region  known  as  the  Idaho  Basin,  an  area  of  some 


1  Eighteenth  Annual  Report  U.  S.  Geological  Survey,  III,  1896-97,  p.  677. 


306  THE  NON-METALLIC  MINERALS. 

150  square  miles  about  the  headwaters  of  Moore  Creek,  in  Boise 
County,  Idaho.  The  mineral  is  here  associated  with  ilmenite, 
garnet,  and  zircon. 

Brazil. — As  above  noted,  the  original  source  of  the  Brazilian 
monazite  were  gneisses  from  which  the  mineral  has  been  liberated 
by  decomposition.  The  particular  localities  examined  by  Professor 
Derby  are  in  the  provinces  of  Minas  Geraes,  Rio  de  Janeiro,  and 
Sao  Paulo.  The  most  extensive  accumulation  thus  far  reported 
is  in  the  form  of  considerable  patches  on  the  sea  beach  near  the 
little  town  of  Alcobaca  in  the  southern  part  of  the  province  of  Bahia, 
though  it  has  been  also  found  on  other  sea  beaches  and  in  river 
sands.  Nitze  states: * 

"Sacks  filled  with  this  sand  were  shipped  to  New  York  in  1885, 
the  deposit  having  been  taken  for  tin  ore.  Its  true  character  was, 
however,  soon  recognized,  and  since  then  a  number  of  tons  have 
been  shipped  in  the  natural  state,  without  any  further  concentra- 
tion or  treatment,  as  ballast,  mainly  to  the  European  markets.  It 
is  reported  to  contain  3  to  4  per  cent  thoria.  .  .  .  Monazite  has 
also  been  found  in  the  gold  and  diamond  placers  of  the  provinces 
of  Bahia  (Salabro  and  Caravellas),  Minas  Geraes  (Diamantia), 
Rio  de  Janeiro,  and  Sao  Paulo.  It  has  been  found  in  the  river  sands 
of  Buenos  Ayres,  Argentine  Republic,  and  also  in  the  gold  placers 
of  Rio  Chico,  at  Antioquia,  in  the  United  States  of  Colombia." 

Russia. — "In  the  Ural  Mountains  of  Russia  monazite  is  found 
in  the  Bakakui  placers  of  the  Sanarka  River.  The  placer  gold 
mines  of  Siberia  are  reported  to  be  rich  in  monazite,  which  is  rafted 
down  the  Lena  and  the  Yenesei  rivers  to  the  Arctic  Ocean,  and 
thence  to  European  ports. 

Norway. — "Economic  deposits  of  monazite  are  also  reported 
to  exist  in  the  pegmatic  dikes  of  Southern  Norway.  It  is  picked 
by  the  miners  while  sorting  feldspar  at  the  mines.  It  is  not  known 
to  exist  in  placer  deposits.  The  annual  output  is  stated  to  be  not 
more  than  i  ton,  which  is  shipped  mainly  to  Germany. 

Methods  of  extraction. — In  the  Carolinas  the  monazite  is  won  by 

1  Sixteenth  Annual  Report  U.  S.  Geological  Survey,  1894-95,  pt.  4,  p.  685. 


PHOSPHATES.  307 

washing  the  sand  and  gravel  in  sluice  boxes  after  the  manner  of 
placer  gold.  Magnetite,  and  other  ferriferous  minerals,  if  present, 
are  eliminated  from  the  dried  sand  by  the  electro-magnet.  Many 
of  the  heavy  minerals,  such  as  zircon,  menaccanite,  rutile,  brookite, 
corundum,  garnet,  etc.,  can  not  be  thus  completely  eliminated,  and 
the  commercially  prepared  sand,  therefore,  is  not  pure  monazite. 
A  cleaned  sand  containing  from  65  to  70  per  cent  monazite  has  in 
the  past  been  considered  of  good  quality,  but  of  late  years  concen- 
trating machines  have  been  introduced  by  means  of  which  sands 
running  as  high  as  80  per  cent  monazite  are  obtained. 

3.    TORBERNITE. 

Composition:  a  hydrous  phosphate  of  uranium  and  copper  of 
the  general  formula  CuO,  2UOs,  P2O5,  8H2O,  which  is  equivalent 
to  uranium  trioxide  (UOs)  61.2  per  cent,  copper  8.4  per  cent,  phos- 
phorous pentoxide  (P2O5)  15.1  per  cent,  water  (H2O)  15.3  per  cent. 
Arsenic  sometimes  replaces,  in  part,  the  phosphorus.  Color,  green; 
when  crystallized  in  the  form  of  small  square  tablets,  sometimes  very 
thin  and  foliated,  in  which  form  it  has  been  called  uranium  mica. 
The  laminae  are,  however,  brittle.  The  mineral  has  been  found 
in  Cornwall,  England,  and  in  Saxony,  Bohemia,  and  Belgium,  but 
in  quantities  of  only  mineralogical  interest.  What  is  reported  as 
a  deposit  of  possible  economic  value  has  recently  been  discovered 
in  the  Province  of  Guarda,  in  Portugal.  Wm.  Nivens  also  reports  1 
the  finding  of  the  material  in  a  vein  from  2  to  6  feet  in  width  near  the 
Cerro  Metafe,  State  of  Guerrero,  Mexico.  Average  samples  are 
reported  to  yield  one-half  of  one  per  cent  of  uranium. 

Uses. — The  rare  elements  cerium,  zirconium,  thorium,  yttrium, 
lanthanum,  etc.,  which  are  as  a  rule  associated  with  each  other 
in  the  minerals  cerite,  zircon,  monazite,  samarskite,  etc.,  as  de- 
scribed,, find  their  commercial  use  not  in  the  form  of  metals,  but 
as  oxides  only ;  and  it  is  only  since  the  introduction  of  the  Welsbach 
incandescent  system  of  lighting  that  their  use  in  this  form  has  assumed 
any  commercial  importance. 

1  The  Mining  World,  Jan.  15,  1910 


308  THE  NON-METALLIC  MINERALS. 

This  Welsbach  light  consists  of  a  cap  or  hood  to  gas  or  other 
burners,  to  increase  their  illuminating  powers.  The  cap  is  made 
of  cotton  or  other  suitable  material,  impregnated  with  the  oxides  in 
proportions  60  per  cent  zirconia,  20  per  cent  yttria,  and  20  per  cent 
lanthanum.  The  fabric  is  strengthened  and  supported  with  fine 
platinum  wire  and  suspended  in  the  flame.  On  igniting  in  the 
flame  the  fabric  is  quickly  reduced  to  ash,  the  cotton  being  burnt 
away  and  the  earthy  matter  still  retaining  the  form  of  a  cap  or  hood.3 

The  drawback  to  the  use  of  these  oxides  has  been,  it  is  said,2 
the  great  difficulty  in  obtaining  them  in  a  pure  condition.  Several 
methods  have  been  used,  but  usually  with  poor  results,  especially 
when  the  mineral  contains  iron.  The  cerium  oxalate  is  used  in 
pharmacy. 

The  demand  for  the  minerals  of  this  group  being  so  limited, 
there  is  no  regular  market  price.  The  Mineral  Industry  for  1893 
quotes  zircon  at  10  cents  a  pound,  monazite,  25  cents,  and  samarskite, 
50  cents.  In  1901  monazite  from  North  Carolina  was  quoted  at 
8  cents  per  pound,  of  which  the  original  miners  received  from  3^-  cents 
to  5  cents  per  pound,  according  to  the  purity  of  the  material.  The 
total  output  of  the  United  States  for  1908  was  422,646  pounds, 
valued  at  $50,718,  or  12  cents  per  pound.  It  is  stated  that  i  ton  of 
zircon  will  yield  sufficient  zirconia  for  half  a  million  Welsbach 
burners.  For  uses  of  torbenite  see  under  Uranates,  p.  330. 

BIBLIOGRAPHY. 

See  paper  on  Monazite,  by  H.  B.  C.  Nitze,  in  Mineral  Resources  of  the  United 
States,  Part  4,  of  the  Sixteenth  Annual  Report  U.  S.  Geological  Survey,  1894-95, 
pp.  667-693.  This  contains  a  very  satisfactory  bibliography  down  to  date  of  publi- 
cation. Also  see  Les  Terres  Rares  Mineralogie-Properties  Analyse,  by  P.  Truchot. 
Carre  et  Naud.  Paris,  1898.  Introduction  to  the  Rare  Elements,  by  P.  E.  Browning. 
Wiley  &  Sons.  New  York,  1903. 

4.    WAVELLITE. 

Wavellite. — This  mineral  is  a  hydrous  phosphate  of  alumina 
corresponding  to  the  formula  3Al2Os2P2O5,  i2H2O.  The  theoreti- 
cally pure  mineral  would  therefore  carry  some  15.37  per  cent  of 

1  Journal  of  the  Society  of  Chemical  Industry,  V,  1886,  p.  522. 

2  Mineral  Resources  of  the  United  States,  1885,  P-  393- 


PHOSPHATES.  309 

phosphorus.  Commonly  :n  globular,  botryoidal,  and  stalatitic  forms 
showing  internally  a  finely  fibrous,  radiate  structure;  rarely  in 
distinct  crystals;  colors,  white,  yellowish,  brown,  or  rarely  greenish 
or  black.  Hardness,  3.25  to  4;  streak  white;  specific  gravity,  2.33. 

Occurrence  and  origin. — The  common  form  of  occurrence  is  as  a 
secondary  mineral  in  residual  clays  and  soils  though  also  found  in 
rifts  and  pockets  of  still  firm  rocks  associated  with  amblygonite  and 
other  phosphates.  It  is  fairly  common  as  a  mineral,  but  rarely 
occurs  in  sufficient  abundance  to  be  of  commercial  value.  At  the 
foot  of  the  northern  slope  of  South  Mountain,  in  the  vicinity  of 
Holly  Springs,  Pennsylvania,  the  mineral  is  found  in  quantity, 
together  with  manganese  ores  and  limonite  in  the  surface  sands, 
gravels,  and  clays,  which  cover  the  rock  outcrops,  and  which  were 
themselves  derived  from  the  neighboring  sandstones,  limestones, 
and  hydro-mica  slates.  It  seems  reasonable  to  conclude,  according 
to  G.  W.  Stose  l  that  the  original  deposition  of  the  iron  (limonite) 
together  with  the  wavellite,  was  in  some  way  a  feature  of  the  change 
of  sedimentation  from  shore  detritus  to  calcareous  silt,  probably 
not  as  a  massive  bed  of  ore  but  as  ferruginous  sediments.  The 
phosphorus  was  probably  associated  with  the  iron  in  its  original 
occurrence  and  in  the  process  of  redeposition  it  combined  with  the 
alumina,  but  it  is  possible  that  a  part  of  the  phosphorus  may  have 
been  derived  from  the  remains  of  invertebrate  animals,  trilobites 
and  other  fossils  being  found  in  the  limestones. 

The  wavellite,  in  form  of  nodular,  disconnected  masses  is  found 
scattered  through  a  white  clay  and  is  mined  by  open  cuts.  The 
output  is  used  in  the  manufacture  of  phosphorus  which,  in  its  turn 
is  consumed  mainly  in  the  manufacture  of  matches. 


5.    AMBLYGONITE. 

This  is  a  fluo-phosphate  of  aluminum  and  lithium  of  the  formula 
Li(AlF)PO4.  Analysis  of  a  sample  from  Paris,  Maine,  as  given 
by  Dana,  shows:  Phosphoric  acid,  48.31  per  cent;  alumina,  33.63 
per  cent;  lithia,  9.82  per  cent;  soda,  0.34  per  cent;  potash,  0.08 

:  Bulletin  No.  315,  U.  S.  Geological  Survey,  1907,  p.  477. 


3io 


THE  NON-METALLIC  MINERALS. 


per  cent;  water,  4.89  per  cent;  fluorine,  4.82  per  cent.  Hardness, 
6;  specific  gravity,  3.01  to  3.09.  Luster  vitreous  to  greasy,  color 
white  to  pale  greenish,  bluish,  yellowish,  to  brownish;  streak  white. 
On  casual  inspection  the  mineral  somewhat  resembles  potash  feld- 
spar (orthoclase) ,  but  when  finely  pulverized  is  soluble  in  sulphuric 
acid,  and  less  readily  so  in  hydrochloric  acid.  Before  the  blowpipe 
the  mineral  gives  the  characteristic  lithia  red  color  to  the  flame. 

Mode  of  occurrence. — Amblygonite  occurs  in  the  form  of  coarse 
crystals,  or  compact  and  columnar  forms  in  pegmatic  dikes  asso- 
ciated with  lepidolite,  tourmaline,  and  other  minerals  so  charac- 
teristic of  this  class  of  rocks.  In  the  United  States  it  occurs  at 
Hebron;  Mount  Mica,  in  Paris;  Auburn  and  Peru,  Maine,  at  the 
last-named  place  associated  with  spodumene,  petalite,  and  lepidolite. 
In  Saxony  the  mineral  is  found  at  Chursdorf  and  Arnsdorf,  near 
Penig,  and  near  Geier.  Also  found  at  Arendal,  Norway,  and  at 
Montebras  and  Creuze,  France. 

Uses. — Since  1886  the  mineral  has  been  utilized  as  a  source  of 
lithia  salts,  in  place  of  the  lithia  mica.  The  chief  commercial 
source  is  at  present  Montebras,  France,  where  it  occurs  in  a  coarse 
granitic  vein  yielding  also  cassiterite  and  kaolin  in  commercial 
quantities.  (See  also  Spodumene,  p.  200.) 


6.    TRIPHYLITE   AND   LITHIOPHILITE. 

These  are  names  given  to  phosphates  of  iron,  manganese,  and 
lithium,  and  which  pass  into  one  another  by  insensible  gradations 
through  variations  in  the  proportional  amounts  of  manganese  pro- 
toxide, the  triphylite  containing  from  10  to  20  per  cent  of  this  oxide, 
while  the  lithiophilite  contains  twice  that  amount.  The  compara- 
tive composition  of  extreme  types  is  shown  below: 


Name. 

P205, 

FeO. 

MnO. 

Li20. 

Na2O. 

H20 

Triphvlite 

4^  l8 

"?6.2  I 

8.96 

8  ic 

o  26 

o  87 

JjithinnhilitP 

4.4.67 

4.02  • 

40.86 

8.6* 

O.I  J. 

o  82 

Triphylite  is  a  gray  to  blue-gray  mineral  in  crystals  and  coarsely 


VANADATES.  311 

cleavable  masses  of  a  hardness  of  4.5  to  5  of  Dana's  scale,  and 
specific  gravity  of  3.42  to  3.56. 

Lithiophilite  differs  mainly  in  color — aside  from  composition 
as  above  noted — being  of  a  pink  to  clove-brown  hue.  Both  minerals 
may  undergo  a  darkening  in  color,  becoming  almost  black  through  a 
higher  oxidation  and  hydration  of  the  manganese  protoxide.  This 
feature  is  best  shown  in  the  lithiophilite  from  B  ranch  ville,  Con- 
necticut. 

Occurrence. — These  minerals  occur  chiefly  in  granitic  veins, 
associated  with  spodumene  and  other  lithia-bearing  minerals,  as 
at  the  localities  above  mentioned.  Peru,  Hebron,  and  Norway, 
Maine,  Keityo,  Finland,  etc.  They  have  as  yet  been  put  to  no 
practical  use. 

7.    VANADINITE. 

This  is  a  vanadinate  and  chloride  of  lead  of  the  formula  (PbCl) 
Pb4V30 12  =  vanadium  pentoxide,  19.4  per  cent;  lead  protoxide, 
78.7  per  cent;  chlorine,  2.5.  In  nature  often  more  or  less  impure 
through  the  presence  of  arsenic  and  traces  of  iron,  manganese, 
zinc,  and  lime.  Color  deep  red  to  brown  and  straw-yellow,  resinous 
luster;  translucent  to  opaque.  Hardness,  2.75  to  3.  Gravity, 
6.66  to  7.23.  When  a  drop  of  nitric  acid  is  applied  to  a  particle 
of  a  crystal  there  is  soon  formed  a  yellow  coating  of  vanadic  oxide. 
This  reaction  is  quite  characteristic  and  furnishes  an  easy  and 
convenient  means  of  determination. 

Localities  and  mode  of  occurrence. — The  mineral  occurs  in  pris- 
matic crystals  with  smooth  faces  and  sharp  edges;  crystals  sometimes 
cavernous  at  the  top.  Also  common  in  parallel  grouped  and  rounded 
forms  and  globular  incrustations.  Dana  gives  the  following  relative 
to  the  known  localities: 

"  This  mineral  was  first  discovered  at  Zimapan  in  Mexico,  by 
Del  Rio.  Later  obtained  among  some  of  the  old  workings  at  Wan- 
lockhead  in  Dumfriesshire,  where  it  occurs  in  small  globular  masses 
on  calamine,  and  also  in  small  hexagonal  crystals;  also  at  Berezov 
in  the  Ural,  with  pyromorphite;  and  near  Kappel  in  Carinthia,  in 
crystals;  at  Undenas,  Bolet,  Sweden;  in  the  Sierra  de  Cordoba, 
Argentine  Republic;  South  Africa. 


312  THE  NON-METALLIC  MINERALS. 

"  In  the  United  States  it  occurss  paringly  with  wulfenite  and  pyro- 
morphite  as  a  coating  on  limestone,  near  Sing  Sing,  New  York.     In 
Arizona  it  is  found  at  the  Hamburg,  Melissa, 
and  other  mines  in  Yuma  County ,  in  .brilliant 
deep-red  crystals;     Vulture,    Phoenix,    and 
other  mines  in   Maricopa   County;    at   the 
Black  Prince  mine ;  also  the  Mammoth  gold 
mine,  near   Oracle,   Pinal    County,    and  in 
brown  barrel-shaped  crystals  in  the  Humbug 
district,  Yavapai  County.     In  New  Mexico 
FIG.  46.— Vanadinite        it  is  found  at  Lake  Valley,  Sierra  County 
crystals.  (endlichite) ;   and  the  Mimbres  mines  near 

Georgetown." 

The  characteristic  mode  of  occurrence  at  the  Mimbres  mines, 
above  noted,  is  associated  with  descloizite  in  the  form  of  small 
hopper-shaped  crystals  and  drusy  or  botryoidal  and  globular  masses 
coating  the  siliceous  residues  of  the  limestone  in  the  irregular  cavities 
with  which  the  stone  abounds.  The  color  of  these  coatings  varies 
from  beautiful  ruby  red  to  light  ocherous  yellow.  The  mineral  is 
here  nearly  always  associated  with  descloizites  as  noted  below. 
Uses. — See  under  Descloizite. 


8.    DESCLOIZITE. 

This  is  a  vanadinate  of  lead  and  zinc  of  the  formula  4(PbZn)O. 
V2O5,H2O,  =  vanadium  pentoxide,  22.7  per  cent;  lead  protoxide, 
55.4  per  cent;  zinc  oxide,  19.7  per  cent;  water,  2.2  per  cent.  The 
published  analyses  show  also  small  amounts  of  arsenic,  copper,  iron, 
manganese,  and  phosphorus.  Color,  red  to  brown;  luster,  greasy;  no 
cleavage ;  fracture  small  conchoidal  to  uneven.  Occurs  in  small  pris- 
matic or  pyramidal  crystals  and  in  fibrous,  mammillated  or  massive 
forms.  Often  associated  with  and  pseudomorphous  after  vanadinite. 

Localities  and  mode  of  occurrence. — Dana  gives  the  following 
relative  to  occurrence: 

"Occurs  in  small  crystals,  i  to  2  millimeters  thick,  clustered 
on  a  siliceous  and  ferruginous  gangue  from  South  America,  at  the 
Venus  Mine  and  other  points  in  the  Sierra  de  Cordoba,  Argentine 


YANADATES.  313 

Republic,  associated  with  acicular  green  pyromorphite,  vanadinite, 
etc.  At  Kappel,  in  Carinthia,  in  small  clove-brown  rhombic  octa- 
hedrons. 

******* 

"  Sparingly  at  the  Wheatley  Mine,  Phcenixville,  Pennsylvania, 
as  a  thin  crystalline  crust  on  wulfenite,  quartz,  and  a  ferruginous 
clay.  Abundant  at  the  Sierra  Grande  Mine,  Lake  Valley,  Sierra 
County,  New  Mexico,  in  red  to  nearly  black  crystals,  pyramidal 
and  prismatic  in  habit,  associated  with  vanadinite,  iodryite,  etc.; 
at  the  Mimbres  and  other  mines,  near  Georgetown,  New  Mexico, 
in  stalactitic  crystalline  aggregates.  In  Arizona  near  Tombstone, 
in  Yavapai  County,  in  brownish  olive-green  crystals;  at  the  Mam- 
moth Gold  Mine,  near  Oracle,  Final  County,  in  orange-red  to 
brownish  red  crystals  with  vanadinite  and  wulfenite." 

A  vanadinite,  probably  identical  with  descloizite,  occurs  at  the 
Mayflower  Mine,  Bald  Mountain  district,  in  Beaverhead  County, 
Montana;  it  is  in  an  impure  earthy  form  of  a  dull  yellow  to  pale 
orange  color.  (See  further  under  Carnotite,  p.  332.) 

Vanadium  is  also  found  in  small  quantities  in  certain  Swedish 
iron  ores;  in  the  cupriferous  schists  of  Mansfeld,  Saxony;  in  cupri- 
ferous sands  of  Cheshire,  England,  and  Perm,  Russia;  in  coals 
from  various  localities;  in  beauxite  and  in  clay  near  Paris.  As 
stated  by  Fuchs  and  De  Launay  ,x  vanadium  has  been  shown  to 
exist  in  extremely  small  proportions  in  primordial  rocks,  from 
which  it  became  concentrated  in  the  clays  on  their  breaking  up. 
Certain  oolitic  iron  ores  (limonites)  at  Mafenay,  Saone  et  Loire, 
France,  contain  the  substance  in  such  proportions  that  the  slags 
from  their  smelting  have  become  commercial  sources  of  supply. 

The  following  referring  to  the  occurrence  and  value  of  vanadinates 
in  the  United  States  is  of  sufficient  interest  to  bear  reproduction 
here: 

The  lead  vanadates  are  frequently  found  in  association  with 
lead  ores,  as,  for  instance,  in  the  deposits  at  Leadville,  whence 
some  very  handsome  specimens  were  formerly  obtained.  The 
most  important  occurrence  of  lead  vanadates  in  the  United  States, 
however,  is  probably  in  Arizona,  where  it  has  been  reported  in  the 

1  Traite  des  Gites  Mineraux,  II,  p.  95. 


314  THE  NGN-METALLIC  MINERALS. 

ores  of  several  mines,  among  others  those  of  the  Castle  Dome  district, 
the  Crowned  King  mine  in  the  Bradshaw  Mountains,  and  the  Mam- 
moth gold  mines  at  Mammoth,  in  Final  County.  The  last-men- 
tioned mines  are  probably  the  only  ones  in  the  United  States  from 
which  vanadium  minerals  have  been  won  on  an  industrial  scale. 
The  vanadium  minerals,  of  which  nearly  all  the  known  varieties 
occurred,  the  dechenite  and  descloizite  predominating,  were  found 
in  the  upper  levels  of  the  mine,  forming  about  i  per  cent  of  the  ore 
on  the  average,  though  within  limited  areas  they  formed  from  3  to 
4  per  cent.  In  the  lower  levels  they  occurred  less  abundantly, 
only  an  occasional  pocket  and  a  small  quantity  of  disseminated 
crystals  being  found.  The  red  crystals,  according  to  an  analysis 
by  the  late  Dr.  F.  A.  Genth,  contained  chlorine,  2.43  per  cent; 
lead,  7.08  per  cent;  lead  oxide,  69.98  per  cent;  ferric  oxide,  0.48  per 
cent;  vanadic  acid,  17.15  per  cent;  arsenic  acid,  3.06  percent, 
and  phosphoric  acid,  0.29  per  cent.  In  milling  the  ore  (gold)  the 
vanadium  minerals  collected  in  riffles.  The  total  quantity  of  con- 
centrates obtained  in  this  manner  did  not  exceed  6  tons.  An  average 
sample  of  the  lot,  analyzed  by  Dr.  Genth,  gave  the  following  results: 
Vanadic  acid,  15.40  per  cent;  molybdic  acid,  3.35  per  cent;  arsenic 
acid,  1.50  per  cent;  carbonic  acid,  0.90  per  cent;  chlorine,  0.48  per 
cent;  oxide  of  lead,  56.80  per  cent;  oxide  of  zinc,  10.70  per  cent; 
oxide  of  copper,  0.95  per  cent;  oxide  of  iron,  0.35  per  cent;  soluble 
silica,  0.60  per  cent;  insoluble  matter,  5.29  per  cent.  The  price 
realized  on  this  first  lot  was  12.5  cents  per  pound,  or  $250  per  ton, 
on  board  the  cars  at  Tucson. 

The  vanadic  salts  manufactured  from  this  lot  of  concentrates 
were  said  to  have  been  the  first  produced  on  a  commercial  scale 
in  the  United  States,  and  owing  to  the  limited  market  for  the  same 
the  price  dropped  over  50  per  cent.  (See  also  under  Patronite, 
p.  41,  and  Roscoelite,  p.  179.) 

Uses. — The  uses  thus  far  developed  for  these  minerals  are  as  a 
source  for  vanadium  salts  used  as  a  pigment  for  porcelain  and  in 
the  manufacture  of  ferro vanadium  alloys  to  be  used  in  steel-making. 
Vanadate  of  ammonium  and  vanadic  oxide  are  used  in  the  manu- 
facture of  ink  and  in  textile  dyeing  and  printing,  imparting  intense 
black  colors  with  a  slight  greenish  cast.  Vanadium  oxide  obtained 


NITRATES.  315 

from  the  slags  of  the  Creusot  steel  works  in  France  is  utilized  as  a 
mordant  in  dyeing.  When  used  in  steel  the  vanadium  is  stated  to 
very  greatly  increase  the  tensile  strength  and  elastic  limit.  A  larger 
supply,  it  is  thought,  would  result  in  its  use  in  armor  plate,  pro- 
jectiles, and  bronzes. 

IX.  NITRATES. 

There  are  three  compounds  of  nitric  acid  and  a  base  occurring 
in  nature  in  such  quantities  and  of  sufficient  economic  importance  to 
merit  attention  here.  These  are  (i)  the  true  niter  or  potassium 
nitrate  (KNO3),  (2)  soda  niter  or  sodium  nitrate  (NaNO3),  and 
(3)  nitrocalcite,  a  calcium  nitrate  (CaN2O6).  All  are  readily  soluble 
in  water,  and  hence  found  in  any  quantity  only  in  arid  regions  or 
where  protected,  as  in  the  dry  parts  of  caves. 

I.    NITER,    POTASSIUM   NITRATE. 

Composition. — KNO3,  =  nitric  anhydride  (NO2),  53.5  per  cent; 
potash  (K2O),  46.5  per  cent.  Hardness,  2;  specific  gravity,  2.1; 
color,  white,  subtransparent.  Readily  soluble  in  water.  Taste, 
saline  and  cooling.  Deflagrates  vividly  when  thrown  on  burning 
coals  and  colors  the  flame  violet. 

The  mineral  occurs  in  nature  mainly  in  the  form  of  acicular 
crystals  and  efflorescences  on  the  surface  or  walls  of  rocks  and 
scattered  in  the  loose  soil  of  limestone  caves  and  similar  dry  and 
protected  places. 

It  is  also  found  in  certain  soils  of  tropical  countries,  as  noted 
later  under  origin  (p.  319).  In  the  United  States  it  has  been  found 
in  caves  of  the  Southern  States,  as  those  of  Madison  County,  Ken- 
tucky, but  never  as  yet  in  commercial  qualities.  The  chief  com- 
mercial source  of  the  salts  has  been  the  artificial  nitraries  of  France, 
Germany,  Sweden,  and  other  European  countries.  It  is  also  pre- 
pared artificially  from  soda  niter. 

2.    SODA   NITER. 

Nitrate  of  sodium,  NaNo3,  =  nitric  anhydride  (NO2),  63.5  per 
cent;  soda  (Na2O),  36.5  per  cent.  This  in  its  pure  state  is  a  white  or 
colorless  salt,  but  in  nature  often  brown  or  bright  lemon-yellow,  rf  a 


31 6  THE  NON-METALLIC  MINERALS. 

slight  saline  taste,  but  with  a  peculiar  cooling  sensation  when  placed 
upon  the  tongue.  It  is  by  far  the  most  common  of  the  nitrates, 
and  indeed  the  only  one  of  the  natural  salts  of  any  great  commercial 
value,  owing  to  the  comparative  rarity  of  the  others.  Though 
found  to  a  slight  extent  in  caves  and  protected  places,  the  commercial 
supply  is  drawn  almost  wholly  from  the  arid  or  pampas  regions  of  the 
Pacific  coast  of  South  America  and  particularly  from  Chile,  the  chief 
deposits  being  found  in  the  provinces  of  Tarapaca  and  Antofagasta. 
According  to  Penrose  l  the  pampas  region  has  a  general  slope 
from  east  to  west.  As  a  result  the  western  border,  where  is  abuts 
against  the  foothills  of  the  coast  range,  is  the  lowest,  and  it  is  along 
this  zone  that  the  nitrate  deposits  occur,  occupying  in  Tarapaca 
province  a  narrow  north  and  south  belt  for  a  distance  of  over  100 
miles.  The  beds  are  all  superficial  deposits,  from  several  to  many 
feet  in  thickness,  and  often  capped  by  several  feet  of  earthy  material. 
Most  of  the  deposits,  it  should  be  noted,  consist  largely  of  sodium 
chloride  (common  salt),  or  a  mixture  of  this  salt  and  the  niter. 
Rarely  does  the  crude  salt  carry  over  70  per  cent  of  niter  and  25 
per  cent  is  considered  a  fair  average.  Sometimes  the  nitrate  de- 
posits are  found  in  the  bottom  of  shallow  basins,  but  more  commonly 
this  position  is  occupied  by  the  chloride  salts,  while  the  nitrate 
forms  terraces  or  benches  around  them.  The  two  salts  may,  how- 
ever, occur  mixed  indiscriminately.  The  deposits,  which  where 
exposed  present  a  rough  and  leached  appearance,  are  quite  variable 
in  thickness  even  over  small  areas,  a  depth  of  several  feet  fading  out 
within  a  few  yards  to  but  a  few  inches.  Thicknesses  of  i  to  i  J  to  3 
feet  are  common;  less  so  are  thicknesses  of  4  to  6  feet.  The  over- 
lying material,  rarely  absent,  varies  from  2  to  20  feet  in  thickness, 
sometimes  to  even  30  or  40  feet.  The  following  section  is  given  for 
the  Province  of  Tarapaca. 

Loose  windblown  material,  sand  and  gravel,  known  as  Chaca o  to  several  feet 

Capping  of  clay,  gravel,  and  sand,  known  as  Costra o  to  20-40  feet 

Crude  nitrate,  known  as  Caliche ,      0-6    " 

Earthy  floor  of  nitrate  beds,  known  as  Coba Indefinite 

Stratified  clays,  sands,  and  gravels 

journal  of  Geology,  Vol.  XVIII,  No.  i,  Jan.-Feb.,  1910. 


NITRATES. 


317 


As  above  noted  the  natural  nitrate  is  never  chemically  pure. 
The  following  analyses  are  selected  to  show  averages: 


ANALYSES   OF   CRUDE   CHILEAN   NITRATE. 


Constituents. 

Per  Cent. 

Sodium  nitrate                    

28    <J4 

C7.   CO 

41    12 

61   07 

22    77 

Potassium  nitrate              

Trace. 

17     2s 

7.4? 

r     i- 

i  6q 

Sodium  chloride                    

17   20 

21.28 

7     ?8 

27   c;c 

41  oo 

Potassium  perchlorate       

Trace. 

0.78 

o   7^ 

O.2I 

Trace. 

Sodium  sulphate         

^  .40 

I  .Q^ 

Trace. 

2.  IT. 

O   Q4 

Magnesium  sulphate  

7    4? 

I  .  2C 

10  o=; 

o.  15 

7     17 

Calcium  sulphate  

2.67 

0.48 

1.86 

O.4I 

4   80 

Sodium  biborate  

0.40 

o.<;6 

O.2O 

O.47 

O    S7 

"        iodide  

0.047 

'  '        iodate  

0.043 

O.OI 

O.Os 

O.Q4 

o  07 

Insoluble  matter 

do  30 

2    O7 

7i  86 

O    7Q 

22    ^O 

Combined  water  etc 

i  88 

O    70 

c    OO 

o  67 

I    7^ 

Total  nitrates   (NaNO3) 

100.00 

28  S4 

100.00 

68  oo 

100.00 
44    OO 

100.00 

66  20 

100.00 
24    1  1 

"      chlorides  (NaCl) 

1  7    2O 

21    28 

3  s8 

27    C  C 

41    OO 

'  '      iodine 

o  067 

o  0064 

o  36 

o  604 

O    Od^ 

Several  of  the  analyses  showed  also  traces  of  calcium  and  mag- 
nesium chlorides,  ammonia  salts,  and  sodium  chromate.  Iodine, 
although  present  in  but  small  proportion,  is  an  important  constituent, 
the  commercial  supply  of  it  being  obtained  almost  wholly  from  the 
nitrate,  in  process  of  refining. 

The  nitrate  deposit  is  quarried  by  blasting  with  a  coarse-grained 
powder,  of  which  as  much  as  150  pounds  are  sometimes  used  at  a 
single  blast.  Neither  dynamite  nor  nitroglycerin  is  used,  as  it 
would  shatter  and  pulverize  the  salt  so  as  to  occasion  a  serious  loss. 

After  being  brought  to  the  surface  the  caliche  is  carefully  assorted 
by  experts,  broken  into  pieces  double  the  size  of  an  orange,  and 
carted  to  the  refinery  establishment,  situated  on  the  pampas  or  on 
the  seacoast,  or  carried  to  Iquique,  Pisagua,  Patillos,  and  Anto- 
fagasta  by  rail,  all  of  these  places  having  connection,  by  narrow- 
gauge  railways,  with  the  nitrate  deposits,  and  which,  consequently, 
are  rapidly  becoming  the  chief  centers  of  nitrate  production  and 
export. 


THE  NON-METALLIC  MINERALS. 


The  following  map,  Fig.  47,  from  Fuchs  and  De  Launay's 
Traitd  des  Gites  Mineraux,  will  serve  to  show  the  geographic  posi- 
tion of  the  deposits. 


Halite   and   Glaettberife 


i££#^£^l  Nitrate    <f  Sodium 


FIG.  47. — Map  of  Chilean  nitrate  region. 
[After  Fuchs  and  De  Launay.] 


3.      NITRO-CALCITE. 

Nitro-calcite,  or  calcium  nitrate,  CaN2O6+wH2O,  is  not  un- 
common as  a  silky  efflorescence  on  the  floors  and  walls  of  dry  lime- 
stone caverns,  and  may  be  extracted  in  considerable  quantities  from 
their  residual  clays  by  a  process  of  leaching.  During  the  war  of 
1812  the  clays  upon  the  floors  of  Mammoth  Cave,  Kentucky,  were 
systematically  leached  and  the  dissolved  nitrate  converted  into 


NITRATES. 


319 


potassium  nitrate  by  filtration  through  wood  ashes.  The  wooden 
tanks  and  log  pipes  for  conducting  the  water  are  still  in  a  remarkable 
state  of  preservation,  owing  to  the  dry  air  of  the  cavern. 

The  nitrous  earths  of  Wyandotte  Cave  in  southern  Indiana,  and 
doubtless  of  other  localities,  were  similarly  treated  during  these 
times  of  temporary  stringency. 

According  to  the  reports  of  the  State  geologist 1  this  earth,  in  its 
air-dry  condition,  has  the  following  composition : 


ANALYSIS   OF  NITROUS  EARTH. 


Constituents. 

Per  Cent. 

Loss  at  red  heat 

16  co 

Silica. 

20  60 

Ferric  oxide 

6  O"? 

Mianganic  oxide 

O    7? 

<\lumina                             . 

2O   40 

Lime 

8  06 

Magnesia                                    .    . 

4.  c8 

Carbonic  acid 

10  28 

Sulphuric  acid               .                    . 

6  « 

Phosphoric  acid                        . 

2    4"? 

Nitric  acid 

3     ^O 

Chlorides  of  alkalies  and  loss 

O    32 

Total 

IOO    IO 

The  researches  of  Muntz  and  Marcano  2  have  shown  that  the 
soils  as  well  as  the  earth  from  the  floor  of  caves,  in  Venezuela  and 
other  portions  of  South  America,  may  be  rich  in  calcium  nitrate  to 
an  extent  quite  unknown  in  other  countries. 

Origin. — The  original  source  of  the  nitrates,  both  of  caves  and  of 
the  Chilean  pampas,  has  been  a  subject  of  considerable  discussion. 
There  appears  little  doubt  but  the  deposits  in  caves  and  those  dis- 
seminated in  soils  are  due  to  the  nitrifying  agencies  of  bacteria 
acting  upon  organic  matter  whereby  the  organic  nitrogen  is  con- 
verted into  nitric  acid,  which  immediately  combines  with  the  most 
available  bases,  be  they  of  lime,  soda,  or  potash.  The  accumulation 


1  Geological  Report  of  Indiana,  1878,  p.  163. 

2  Comptes  Rendus  de  1'Academie  des  Sciences,  CI,  Paris,  1885,  p.  1265. 


320  THE  NON-METALLIC  MINERALS. 

of  the  niter  in  caves  is  probably  due,  as  suggested  by  W.  H.  Hess,1 
to  the  retention  by  the  clay  of  the  nitrates  brought  in  from  the  sur- 
face by  percolating  waters.  In  other  words,  the  caves  serve  merely 
as  receptacles,  or  storehouses,  for  nitrates  which  had  their  origin 
in  the  surface  soil.  The  Chilean  nitrate  beds  are  considered  by 
Muntz  and  Marcano  as  having  a  very  similar  origin.  The  material 
being  soluble  is  gradually  leached  out  from  the  soils  in  which  it 
originated  and  drained  into  inclosed  salt  marshes  or  inland  seas 
where  a  double  decomposition  takes  place  between  the  sodium 
chloride  and  calcium  nitrate,  whereby  sodium  nitrate  and  calcium 
chloride  are  produced.  That  such  a  double  decomposition  may 
take  place  has  been  shown  by  actual  experiment. 

This  is  not  widely  different  from  the  view  taken  also  by  W.  New- 
ton.2 After  discussing  briefly  theories  previously  advanced,  includ- 
ing Darwin's  theory  of  derivation  from  decomposing  seaweeds 
accumulated  on  old  sea  beaches,  and  the  even  less  plausible  one  of  its 
derivation  from  guano,  his  writer  shows  that  the  Tamarugal  plain 
within  which  the  deposits  lie,  is  covered  by  an  alluvial  soil  rich  in 
organic  matter.  This  organic  matter,  under  the  now  well-known 
action  of  bacteria,  aided  by  the  prevailing  high  temperatures  of  the 
region,  gives  rise  to  nitrates,  which,  owing  to  the  absence  of  rains  for 
long  periods,  accumulate  to  an  extent  impossible  under  less  favorable 
circumstances.  Mountain  floods,  which  occur  at  periods  of  seven 
or  eight  years,  swamp  the  plain,  bringing  in  solution  the  nitrate 
drained  from  the  soils  of  the  surrounding  slope,  to  accumulate  in 
the  lower  levels.  On  the  evaporation  of  the  water  this  is  again 
deposited.  The  occurrence  of  the  nitrate  so  far  up  the  slope  of  the 
hills  is  regarded  by  Newton  as  due  to  the  tendency  of  the  nitrate 
salt,  in  saturated  solutions,  to  creep  up,  as  in  experiment  it  may 
be  seen  to  creep  up  and  over  the  sides  of  a  saucer  or  other  shallow 
dish  in  which  the  evaporation  is  progressing. 

Penrose,  on  the  other  hand,  in  the  most  recent  paper  bearing 
on  the  subject,  argues  that  the  nitrogenous  matter  was  derived 
from  ancient  guano  deposits  which  once  lined  the  waters  of  these 
inclosed  basins. 

1  Journal  of  Geology,  VIII,  No.  2,  1900,  p.  129. 

2  Geological  Magazine,  III,  1896,  p.  339. 


BORATES.  321 

Uses. — Munroe  1  gives  the  consumption  ol  nitrate  of  soda  in  the 
United  States  for  1905  as  254,772  short  tons,  which  was  divided 
among  the  various  industries  as  follows: 

In  the  manufacture  of  fertilizers 42,213  tons 

"                  "             dyestuffs 261  " 

"                                 chemicals 38,048  " 

"                                 glass n,9I5  " 

"                   "              explosives 133,034    " 

"  sulphuric,  nitric,  and  other 

acids 29,301  ' ' 

254,772    " 

BIBLIOGRAPHY. 

M.  A.  MUNTZ.     Recherches  sur  la  formation  des  gisements  de  nitrate  de  soude. 

Comptes  Rendus  de  1'Academie  des  Sciences,  CI,  1885,  P- 
RALPH  ABERCROMBY.     Nitrate  of  Soda,  and  the  Nitrate  Country. 

Nature,  XL,  1889,  p.  186. 
WILLIAM  NEWTON.     The  Origin  of  Nitrate  in  Chile. 

The  Geological  Magazine,  III,  1896,  p.  339. 
W.  H.  HESS.     The  Origin  of  Nitrates  in  Caves. 

Journal  of  Geology,  VIII,  No.  2,  1900,  p.  129. 
R.  A.  F.  PENROSE.     The  Nitrate  Deposits  of  Chile. 

Journal  of  Geology,  XVIII,  1910,  pp.  1-32. 


X.  BORATES. 

Of  the  ten  or  more  species  of  natural  borates  but  three,  or  pos- 
sibly four,  are  commercial  sources  of  borax,  and  need  consideration 
here.  These  are,  (i)  borax  or  tincal;  (2)  ulexite,  or  boronatrocal- 
cite;  (3)  priceite,  colemanite,  or  pandermite,  and  (4)  boracite,  or 
stassfurtite.  Sassolite,  or  native  boric  acid,  occurs  chiefly  in  solution. 
The  intimate  associatron  of  these  minerals  renders  it  advisable  to 
treat  of  their  origin  and  mode  of  extraction  in  common,  after  giving 
the  composition  and  general  physical  characters  of  each  by  itself. 

1  The  Nitrogen  Question,  etc.     Proceedings  U.  S.  Naval  Institute,  XXXV,  No.  3, 
1910,  p.  715. 


322  THE  NON-METALLIC  MINERALS. 

i.  BORAX  OR  TINCAL;    BORATE  OF  SODA. 

Composition. — Na2B4O7.ioH2O,=  boron  trioxide,  36.6  per  cent; 
soda,  16.2  per  cent;  water,  47.2  per  cent.  Color,  white  to  grayish, 
and  sometimes  greenish;  translucent  to  opaque.  It  crystallizes  in 
short,  stout  prisms,  belonging  to  the  monoclinic  system.  Hardness, 
2  to  2.5;  specific  gravity,  1.7.  Readily  soluble  in  water;  taste, 
sweetish  alkaline. 

2.  ULEXITE;  BORONATROCALCITE. 

Composition. — NaCaB5O9.8H2O,=  boron  trioxide,  43  per  cent; 
lime,  13.8  per  cent;  soda,  7.7  per  cent;  water,  35.5  per  cent.  Color, 
white,  with  silky  luster.  Occurs  usually  in  rounded  masses  of  loose 
texture,  which  consist  mainly  of  fine  acicular  crystals  or  fibers.  In- 
soluble in  cold  water,  and  only  slightly  so  in  hot,  the  solution  being 
alkaline.  Hardness,  i;  specific  gravity,  1.65. 

3.    COLEMANITE. 

Composition. — Ca2B0On.5H2O,  =  boron  trioxide,  50.9  per  cent; 
lime,  27.2  per  cent;  water,  21.9  per  cent.  Color,  milky  to  yellowish 
white,  or  colorless;  transparent  to  translucent.  Hardness,  4  to  4.5; 
specific  gravity,  2.41.  Insoluble  in  water,  but  readily  so  in  hot  hydro- 
chloric acid.  Priceite  and  pandermite  are  closely  allied  varieties 
occurring  in  loosely  coherent  and  chalky  or  massive  forms. 

4.    BORACITE   OR   STASSFURTITE ;    BORATE   OF  MAGNESIA. 

Composition. — Mg7Cl2B16O30,  =  boron  trioxide,  62.5  percent;  mag- 
nesia, 31.4  per  cent;  chlorine,  7.9  per  cent.  Color,  white  to  yellow 
or  greenish.  In  crystals  transparent  to  translucent.  Crystals  cubic 
and  tetrahedral.  Insoluble  in  water;  readily  soluble  in  hydrochloric 
acid.  Hardness,  7;  specific  gravity,  2.9  to  3. 

Localities  and  manner  of  occurrence  of  the  borates. — Throughout 
what  is  known  as  the  Great  Basin  region  of  the  western  United  States, 
and  in  particular  that  portion  including  Inyo,  Kern,  and  San  Bernar- 
dino counties  in  California,  and  that  portion  of  southwest  Nevada 


BO  RATES.  323 

adjoining  Inyo  County,  are  numerous  inclosed  lakes  or  marshes,  the 
waters  of  which  are  sufficiently  rich  in  borates  and  other  sodium 
salts  to  allow  of  their  extraction  on  a  commercial  scale.  At  least 
ten  of  these  marshes  have  been  noted  along  the  California-Nevada 
line,  the  most  widely  known  being  Teels,  Columbus,  and  Rhodes 
marshes,  and  Fish  Lake  Valley  in  Nevada,  and  Searles  Marsh  in  San 
Bernardino  County,  California.  A  detailed  description  of  the  last 
named  will  serve  all  purposes  of  illustration  here.1 

Locally  considered,  the  marsh  lies  near  the  center  of  an  exten- 
sive mountain-girdled  plain,  to  which  the  names  "  Alkali  Flat," 
"  Dry  Lake,"  "  Salt  Bed,"  and  "  Borax  Marsh  "  have  variously 
been  applied.  It  is,  in  fact,  a  dry  lake,  the  bed  of  which  has  been 
filled  up  in  part  with  the  several  substances  named.  Its  contents 
consist  of  mud,  alkali,  salt,  and  borax,  largely  supplemented  with 
volcanic  sand.  This  depression,  which  has  an  elevation  of  1,700 
feet  above  sea-level,  and  an  irregular  oval  shape,  is  about  10  miles 
long  in  a  north  and  south  direction,  and  5  miles  wide.  It  is  sur- 
rounded on  every  side  but  the  south  by  high  mountains,  the  Slate 
Range  bounding  it  on  the  east  and  north,  and  the -Argus  Range  on 
the  west. 

What  may  have  been  the  depth  of  the  lake  has  not  yet  been  ascer- 
tained, borings  put  down  300  feet  having  failed  to  reach  bed  rock. 
These  borings,  commenced  in  1878,  disclosed  the  following  under- 
lying formations: 

First,  2  feet  of  salt  and  thenardite  (Na2SO4) ;  second,  4  feet  of 
clay  and  volcanic  sand,  containing  a  few  crystals  and  bunches  of 
hanksite  (4Na2SO4,Na2CO3) ;  third,  8  feet  of  volcanic  sand  and 
black,  tenacious  clay,  with  bunches  of  trona,  of  black,  shining  luster 
from  inclosed  mud;  fourth,  8-foot  stratum,  consisting  of  volcanic 
sand  containing  glauberite,  thenardite,  and  a  few  flat,  hexagonal 
crystals  of  hanksite;  fifth,  28  feet  of  solid  trona  of  uniform  thickness; 
sixth,  20-foot  stratum  of  black,  soft  mud,  smelling  strongly  of  sul- 
phur eted  hydrogen,  in  which  there  are  layers  of  glauberite,  soda, 
and  hanksite;  seventh,  230  feet  (as  far  as  explored)  of  brown  clay, 
mixed  with  volcanic  sand  and  permeated  with  sulphureted  hydrogen. 

1  From  the  Tenth  Annual  Report  of  the  State  Mineralogist  of  California,  1890,  p. 534. 


324 


THE  NON-METALLIC  MINERALS. 


While  most  of  the  water  contained  in  this  basin  is  subterranean, 
a  little  from  atmospheric  sources  accumulates  during  very  wet  winters 
and  stands  for  a  short  time  on  portions  of  the  surface.  In  no  place, 
however,  does  it  reach  a  depth  of  more  than  a  foot  or  two,  hardly 
anywhere  more  than  3  or  4  inches. 

The  water  of  the  lake  is  of  a  dark-brown  color,  strongly  impreg- 
nated with  alkali,  and  has  a  density  of  28°  Baume.  The  salts  ob- 
tained from  it  by  crystallization  contain  carbonate  and  chloride 
and  borate  of  sodium,  with  a  large  percentage  of  organic  matter. 

Summarized,  the  following  minerals  have  been  found  associated 
with  the  borax  occurring  in  the  Searles  Marsh:  Anhydrite,  calcite, 
celestite,  cerargyrite,  colemanite,  dolomite,  embolite,  gay-lussite, 
glauberite,  gypsum,  halite,  hanksite,  natron,  soda,  niter,  sulphur, 
thenardite,  tincal,  and  trona,  the  most  of  them  occurring  in  only 
small  quantities. 

The  submerged  tract  above  described  is  called  the  "  Crystal  Bed," 
the  mud  below  the  water  being  full  of  large  crystals,  which  occur  in 
nests  at  irregular  intervals  to  a  depth  of  3  or  4  feet.  Many  of  these 
crystals,  which  consist  of  carbonate  of  soda  and  common  salt  with 
a  considerable  percentage  of  borate,  are  of  large  size,  some  of  them 
measuring  7  inches  in  length.  The  water  15  feet  below  this 
stratum  of  mud  contains  carbonate  of  soda,  borax,  and  salts  of 
ammonia.  The  ground  in  the  immediate  vicinity,  a  dry,  hard  crust 
about  i  foot  thick,  contains: 


Constituents. 

Per  Cent. 

Sand 

CQ 

Sulphate  of  soda 

16 

Common  salt 

I  2 

Carbonate  of  soda   . 

IO 

Borax          '          .          

12 

The  borax  here  occurs  in  the  form  of  the  borate  of  soda  only,  no 
ulexite  (borate  of  lime)  having  yet  been  found. 

About  1890  it  was  discovered  that  these  marsh  deposits  were  all 
secondary,  the  borax  contents  being  derived  from  bedded  deposits 
of  colemanite  in  the  Tertiary  lake  sediments  of  the  surrounding 


BO  RATES. 


325 


hills.  The  marshes  were,  therefore,  very  generally  abandoned  in 
favor  of  the  beds.  What  was,  until  recently,  the  most  important 
of  these  deposits  is  at  a  locality  appropriately  named  Borate,  some 
12  miles  north  of  Daggett  in  the  old  Calico  Mining  District.  The 
mineral  colemanite — the  borate  of  lime — occurs  here  in  beds  of 
from  3  to  5  feet  thickness  interstratified  w;th  Jake  sediments  which 


FIG.  48. — Section  of  tilted  borate  beds,  Furnace  Valley,  California. 

1.  Andesite  (exposed) 

2.  Clay-shale,  blue  above,  yellowish  below 

3.  Gravels,  coarse,  little  or  no  clay 

4.  Basalt - 

5.  Shale,  argillaceous  and  sandy,  buff 

Unconformity. 

6.  Clay,  shaly,  colemanite  in  large  nodules  and  nodular  layers 

7.  Clay,  shaly,  olive-green  to  yellow 

8.  Basalt,  surface-flow 

9.  Clay,  shaly,  yellow  to  green 

10.  Sandstone,  friable,  red  in  color 

1 1 .  Clay,  shaly,  pale  yellow 

12.  Basalt,  black,  surface-flow 

13    Clay,  shaly,  argillaceous,  yellowish 

14.  Clays  and  gravels,  pale  reddish-brown  and  purple 

Unconformity,  very  marked. 
[After  C.  R.  Keyes,  Bulletin  of  the  American  Institute  of  Mining  Engineers, 


500  ft. 

1000  " 

300" 

200" 


50" 

60  " 

IOO  " 

150" 

25" 

500" 

50" 

200" 
500  " 

1909.] 


are  composed  of  semi-indurated  clays,  sandstones,  and  coarse  con- 
glomerates with  sheets  of  volcanic  tuffs  and  lava.  At  the  mine, 
according  to  Messrs.  W.  H.  Storms  l  and  M.  R.  Campbell,2  there 
are  two  outcrops  some  50  feet  apart,  representing  two  distinct  beds 
or  perhaps  a  repetition  by  folding  of  what  was  originally  one  and 
the  same  bed.  These  throughout  their  extent  vary  from  5  to  30 
feet  in  thickness,  and  have  a  strike  approximately  east  and  west, 

1  Eleventh  Annual  Report  of  the  State  Mineralogist  of  California,  1892,  p.  345. 

2  Bulletin  No.  200,  U.  S.  Geological  Survey,  Series  A,  Economic  Geology,  p.  7. 


326 


THE   NON-METALLIC  MINERALS. 


dipping  to  the  south  from  10°  to  45°.  The  lake  beds  extend  across 
the  mountains  for  a  distance  of  8  miles,  but  the  borax  deposit,  so 
far  as  yet  discovered,  has  a  practical  limit  of  not  above  a  mile  and 
a  half.  The  illustration  (Plate  XXX),  conveys  better  than  words 


Sketch  Map  of 
BORATE  DEPOSITS 

of 

CALIFORNIA 
Scale  of  Miles 


50 


Shaded  areas  are 
explored  districts 


P  A   C  I  F   I 
OCEAN 


Fig.  49. — Sketch  map  of  California  borax  localities. 
[After  C.  R.  Keyes,  Bulletin  of  the  American  Institute  of  Mining  Engineers,  1909.] 

an  idea  of  the  character  of  the  desolate  country  in  which  the  borax 
occurs,  and  also  the  method  of  mining. 

.  For  a  decade  or  more,  according  to  C.  R.  Keyes,1  the  mines  at 
Daggett  were  the  chief  source  of  borax  in  the  United  States.  Re- 
cently extensive  developments  have  taken  place  in  Furnace  Canon 
in  Death  Valley  and  in  the  Santa  Clara  Valley,  south  of  the  Sierra 
Madre  and  west  of  Daggett.  (See  map,  Fig.  49.)  At  the  first- 
named  locality  the  borax  deposits  lie  in  a  deep  valley  and  canyon 
between  high  mountain  ranges,  and  in  beds  consisting  mainly  of 


1  Borax   Deposits  of  the   United   States,  Bulletin  American  Institute  of   Mining 
Engineers,  October,  1909,  pp.  1-37. 


3  -    ^ 


<W     p'    X 

' 


< 
8" 

"5  -  3 


BO  RATES.  327 

soft  clays,  and  sands  or  friable  sandstone,  the  mountains  on  either 
hand  being  composed  of  eruptive  and  metamorphic  rocks. 

The  rich  borate  beds  are  from  a  few  inches  to  50  feet  in  thick- 
ness, often  highly  tilted  and  folded  as  shown  in  the  accompanying 
typical  section  (Fig.  48).  They  are  described  as  consisting  of  bluish 
clays,  thickly  interspersed  with  milk-white  layers,  nodular  bands  and 
nodules  of  crystallized  colemanite,  the  clays  yielding  by  leaching 
from  10  to  25  per  cent  of  boric  acid.  Mingled  with  the  colemanite 
there  is  often  much  selenite  in  large  plates. 

In  the  Santa  Clara  Valley  the  entire  borax-bearing  formation 
is  described  as  from  5,000  to  8,000  feet  in  thickness,  consisting 
mainly  of  fine,  more  or  less  indurated  gravel,  yellow  sandstone  and 
clays.  The  beds  have  been  much  faulted  and  flexed  and  intruded 
by  dikes  of  igneous  rocks. 

Borax  in  the  form  of  colemanite  (priceite)  has  also  been  found 
about  5  miles  north  of  Chetco,  in  Curry  County,  Oregon. 

A  borax  deposit  in  form  somewhat  resembling  the  marsh  deposits 
of  Nevada  and  California  already  referred  to  occurs  in  Harney 
County,  southeastern  Oregon.  The  region  is  extremely  flat  and 
bare  of  all  vegetation,  the  immediate  surface  of  the  ground  being 
covered  for  a  depth  of  several  inches  with  a  white  incrustation  con- 
sisting of  the  borate  contaminated  with  carbonate,  sulphate,  and 
chloride  of  sodium.1 

The  chief  foreign  sources  of  borax  salts  are  Northern  Chile, 
Stassfurt  in  Germany,  Italy,  Asia  Minor,  and  Thibet. 

The  Chilean  mineral  is  ulexite  and  is  reported  as  occurring 
throughout  the  province  of  Atacama  and  the  newly  acquired  por- 
tions of  Chile.  Ascotan,  which  is  now  on  the  borders  of  the  Republic, 
but  formerly  belonged  to  Bolivia,  and  Maricunga,  to  the  north  of 
Copeapo,  are  the  places  which  have  proved  most  successful  com- 
mercially. The  crude  material  occurs  in  both  places  in  lagoons 
or  troughs.  Those  of  Maricunga  lie  about  64  kilometers  from  the 
nearest  railway  station,  and  are  estimated  to  cover  3,000,000  square 
meters.  The  boronatrocalcite  occurs  in  beds  alternating  with  layers 
of  salt  and  salty  earth.  The  crude  material  contains,  in  the  form  of 
gypsum  and  glauberite,  a  large  amount  of  calcium  sulphate. 

1  W.  B.  Dennis,  Engineering  and  Mining  Journal,  April  26,  1902,  p.  581. 


328  THE   NON-METALLIC  MINERALS. 

Recently  deposits  have  been  described  in  the  dry  bed  of  Lake 
Salinas,  about  12  miles  east  of  Arequipa  City.  The  borate  is 
in  the  form  of  ulexite  and  in  a  massive  impure  form  known  as 
corriente.  A  section  of  the  deposit  shows  (i)  chloride  and  sulphate  of 
soda  and  fine  sand  10  to  14  cm.;  (2)  gravel  6  cm.;  (3)  sand  with 
layers  of  the  borate  20  to  50  cm. ;  (4)  fine  sand  and  borate  in  variable 
thicknesses  40  cm.  to  i  meter.  The  lake  lies  at  an  altitude  of  14,200 
feet  and  is  surrounded  by  high  mountains,  many  of  which  are 
volcanic.1 

Dana  also  mentions  ulexite  as  occurring  in  the  form  of  rounded 
masses  from  the  size  of  a  hazelnut  to  that  of  a  potato  in  the  dry 
plains  of  Iquique,  where  it  is  associated  with  pickeringite,  glauberite, 
halite,  and  gypsum. 

The  German  mineral  is  boracite  (stassfurtite)  and  is  found  in 
small  granular  masses  associated  with  the  salt  deposits  of  Stassfurt. 
In  Italy  sassolite,  or  crystallized  boric  acid,  has  long  been  obtained 
by  the  evaporation  of  the  water  of  hot  springs  in  Siena,  in  Tuscany. 
Concerning  the  deposits  of  Asia  Minor  little  is  accurately  known. 
The  mineral  is  pandermite  (colemanite) ,  which  is  found  in  thick 
white  lumps  at  Suzurlu,  south  of  the  sea  of  Marmora.  Borax  or 
tincal,  from  Thibet,  in  Northern  India,  was  probably  the  first  of 
the  boron  salts  to  be  utilized.  It  is  stated  to  have  been  brought  on 
the  backs  of  sheep  from  the  lakes  in  which  it  is  formed  across  the 
Himalayas  to  the  shipping  points  in  India. 

Methods  of  mining  and  manufacture. — At  the  East  Calico  Cole- 
manite Mine,  in  San  Bernardino  County,  the  borax  mineral  is  taken 
out  in  the  same  manner  as  ores  of  the  precious  metals.  Inclined 
shafts  are  sunk,  drifts  and  levels  run,  and  slopes  carried  up  as  in 
any  other  mine.  The  material,  when  hoisted  to  the  surface,  is 
loaded  into  wagons  and  hauled  to  Daggett,  whence  it  is  shipped  to 
the  works  at  Alameda,  where  it  is  purified. 

At  Searle's  marsh  the  overlying  crust  mentioned  constitutes  the 
raw  material  from  which  the  refined  borax  is  made.  The  method 
of  collecting  it  in  the  past  has  been  as  follows:  When  the  crust, 
through  the  process  of  efflorescence,  has  gained  a  thickness  of  about 

1  Engineering  and  Mining  Journal,  LXXXIV,  1907,  p.  780. 


BORA1ES. 


329 


i  inch,  it  is  broken  loose  and  scraped  into  windrows  far  enough 
apart  to  admit  the  passage  of  carts  between  them,  and  into  which 
it  is  shoveled  and  carried  to  the  factory  located  on  the  northwest 
margin  of  the  flat,  i  to  2  miles  away. 

As  soon  as  removed,  this  incrustation  begins  again  to  form,  the 
water  charged  with  the  saline  matter  brought  to  the  surface  by  the 
capillary  attraction  evaporating  and  leaving  the  salt  behind.  This 
process  having  been  suffered  to  go  on  for  three  or  four  years,  a 
crust  thick  enough  for  removal  is  again  formed,  the  supposition 
being  that  this  incrustation,  if  removed,  will  in  like  manner  go  on 
reproducing  itself  indefinitely.1 

At  the  Harney  County,  Oregon,  works  the  crude  material  is  care- 
fully shoveled  up  during  the  summer  into  small  conical  heaps,  the 
crust  continually  renewing  itself,  so  that  the  same  ground  is  worked 
over  repeatedly.  This  crude  material,  which  contains  from  5  to 
20  per  cent  boric  acid,  is  refined  by  throwing  into  tanks  of  hot  water 
into  which  small  amounts  of  chlorine  or  sulphuric  acid  are  introduced. 
The  various  salts  are  all  dissolved  and  subsequently  separated  one 
from  another  by  fractional  crystallization. 


1  In  order  to  determine  the  proportionate  growths  of  the  various  salts  contained 
in  this  crust  while  undergoing  this  recuperative  process,  analyses  were  made  on  sam- 
ples representing  respectively  six  months',  two,  three,  and  four  years'  growth.  From 
the  ground  from  which  these  were  taken  the  crust  had  been  removed  several  times 
during  the  preceding  twelve  years. 

The  analysis  of  samples  gave  the  following  results: 


Six 

Two 

Three 

Four 

Constituents. 

Months' 

Years- 

Years' 

Years- 

Growth. 

Growth. 

Growth. 

Growth. 

Sand. 

<;8o 

r  r  A 

£  T.  1 

Carbonate  of  soda.  .  . 

5-2 

8.1 

33-6 

8.0 

Sulphate  of  soda  

11.7 

6.7 

16.6 

16.0 

Chloride  of  soda  

10.9 

2O.O 

II.  I 

11.8 

Borax  .... 

14.  2 

ii  8 

Total.  . 

IOO  O 

From  this  list  it  will  be  seen  that  the  first  six  months'  growth  is  richest  in  borax, 
and  that  the  proportion  of  carbonate  of  soda  to  borax  increases  with  time.  The 
presence  of  so  much  sand  as  is  here  indicated  is  caused  by  the  high  winds  that  blow 
at  intervals,  bringing  in  great  quantities  of  that  material  from  the  mountains  to  the 
west.  This  sand,  it  is  supposed,  facilitates  the  formation  of  the  surface  crust  by 
keeping  the  ground  in  a  porous  condition. 


330 


THE  NON-METALLIC  MINERALS. 


XI.  URANATES. 

i.  URANINITE;  PITCHBLENDE. 

Composition  very  complex,  essentially  a  uranate  of  uranyl,  lead, 
thorium,  and  other  metals  of  the  lanthanum  and  yttrium  groups. 
The  mineral  is  unique  in  containing  nitrogen,  argon,  helium  and 
radium.  The  analyses  given  below  are  for  the  most  part  by  Hille- 
brand,  to  whom  is  due  the  credit  of  a  large  share  of  the  present 
knowledge  on  the  subject. 


Locality. 

UO3. 

U02. 

ThO2. 

Ce02. 

Lao03. 

Y203. 

Glastonbury,  Connecticut.  . 
North  Carolina, 

23-03 
50-83 
30-63 
59-3° 

59-93 
39-31 
46.13 
22.33 

2.78 
6.00 

II 
0.26 
0.18 

10 

0.50 

0.27 

0.20 
I.  II 

Annerod   Norway       ... 

Locality. 

PbO. 

CaO. 

N. 

H2O. 

Fe2O3. 

Misc. 

Glastonbury,  Connecticut.. 
North  Carolina             ... 

3.08 
4.20 
9.04 
6-39 

O.II 

0.85 
o-37 

I.OO 

2.41 

0-37 
1.17 

0.02 

o-43 

1.  21 
0-74 

3-J7 

0.29 

I.  II 
0.48 
4.66 
5-53 

Annerod   Norway   

0.25 

0.21 

Johanngeorgenstadt  

Several  varieties  of  uraninite  are  recognized,  the  distinctions  being 
based  upon  the  relative  proportions  of  the  two  oxides  UO2  and 
UO3  (see  analyses  above).  Inasmuch,  however,  as  these  variations 
may  be  due  merely  to  oxidation  they  need  not  be  taken  into  considera- 
tion here.  When  crystallized  the  mineral  assumes  octahedral  and 
dodecahedral  forms,  more  rarely  cubes.  Hardness,  5.5;  specific 
gravity,  9  .to  9.7.  Color,  grayish,  greenish  to  velvet-black,  streak 
brown;  fracture  conchoidal,  uneven.  The  massive  and  probably 
amorphous  variety  is  known  under  the  name  of  pitchblende.  This 
last  is  the  chief  commercial  source  of  uranium  salts,  and  is  the 
common  "  ore "  of  radium.  Through  oxidation  and  hydration 
the  mineral  passes  into  gummite,  a  gum-like  yellow  to  brown  or  red 
mineral  of  a  hardness  of  but  2.5  to  3  and  specific  gravity  of  3.9  to  4.2. 

Localities  and  mode  of  occurrence. — Uraninite  occurs  as  a  pri- 
mary constituent  of  granitic  rocks  and  as  a  secondary  mineral,  with 
sulphide  ores  of  silver,  lead,  gold,  copper,  etc.  In  this  last  form, 


URANATES.  331 

according  to  Dana,  it  is  found  at  Johanngeorgenstadt,  Marienberg, 
and  Schneeberg,  Saxony;  at  Joachimsthal  and  Pribram,  in  Bohemia, 
and  Rezbanya,  in  Hungary.  Considerable  quantities  have  been 
mined  from  the  tin-bearing  lodes  of  Cornwall,  England.  The 
crystallized  variety  broggerite  is  found  in  a  pegmatite  vein  near 
Annerod,  Norway,  and  the  variety  cleveite  in  a  feldspar  quarry  at 
Arendal.  In  the  United  States  the  mineral  has  been  found  in  small 
quantities  in  several  localities,  but  only  those  of  Mitchell  and  Yancey 
counties,  North  Carolina,  where  the  mineral  occurs  partially  altered 
to  gummite  and  uranaphane,  in  mica  mines;  Llano  County,  Texas; 
Black  Hawk,  near  Central  City,  Gilpin  County,  Colorado,  and 
the  Bald  Mountain  district  of  the  Black  Hills  of  South  Dakota  need 
here  be  mentioned.  Of  the  above  the  Cornwall  localities  are  at 
present  of  greatest  consequence,  having  during  1890  yielded  some 
22  tons  of  ore,  valued  at  some  £2,200  ($11,000).  During  1891,  it 
is  stated,  the  output  was  31  long  tons,  valued  at  £620,  and  in  1892, 
37  tons,  valued  at  £740.  The  next  most  important  locality  is  that 
of  Joachi  -nsthal,  in  Bohemia,  where  22.52  metric  tons  of  ore  were 
produced  in  1891  and  17.71  tons  in  1892,  the  value  being  some  1,000 
florins  a  ton. 

In  the  Cornwall  mines  the  pitchblende  is  stated1  to  occur  in  small 
veins  crossing  the  tin-bearing  lodes.  At  the  St.  Austell  Consols 
Mines  it  was  associated  with  nickel  and  cobalt  ores;  at  Dolcoath 
with  native  bismuth  and  arsenical  cobalt  in  a  matrix  of  red  quartz 
and  purple  fluorspar;  at  South  Tresavean  with  kupfer-nickel,  native 
silver,  and  argentiferous  galena.  At  the  Wood  Lode,  Russell  dis- 
trict, in  Gilpin  County,  Colorado,  pitchblende  was  found  in  the  form 
of  a  lenticular  mass  in  one  of  the  ordinary  gold-bearing  lodes  trav- 
ersing the  gneiss  and  mica  schists  of  the  district.  The  body  occurred 
some  60  feet  below  the  surface  and  was  some  30  feet  long  by  10  feet 
deep  and  10  inches  thick.  The  mass  yielded  some  4  tons  of  ore 
carrying  70  per  cent  oxide  of  uranium. 

Other  natural  uranium  compounds,  but  which  at  present  have 
no  use  in  the  arts,  are  as  below:  Torbenite,  a  hydrous  phosphate 
of  uranium  and  copper  (see  p.  307) ;  autunite,  a  hydrous  phosphate 

1  The  Mineral  Industry,  II,  p.  572. 


33 2  THE  NON-METALLIC 

of  uranium  and  calcium;  zeunerite,  an  arsenate  of  uranium  and 
copper;  uranospinite,  an  arsenate  of  uranium  and  calcium;  uran- 
ocircite,  a  phosphate  of  barium  and  uranium;  phosphuranylite,  a 
hydrous  uranium  phosphate;  trogerite,  a  hydrous  uranium  arsenate; 
walpurgite,  probably  an  arsenate  of  bismuth  and  uranium;  and 
uranosphaerite,  a  uranate  of  bismuth. 

Uses. — Uranium  is  never  used  in  the  metallic  state,  but  in  the 
form  of  oxides,  or  as  uranate  of  soda,  potash,  and  ammonia,  finds  a 
limited  application  in  the  arts.  The  sesquioxide  salt  imparts  to 
glass  a  gold-yellow  color  with  a  beautiful  greenish  tint,  and  which 
exhibits  remarkable  fluorescent  properties.  The  protoxide  gives  a 
beautiful  black  to  high-grade  porcelains.  The  material  has  also  a 
limited  application  in  photography.  Recently  the  material  has  been 
used  to  some  extent  in  making  steel  in  France  and  Germany,  but 
the  industry  has  not  yet  passed  the  experimental  stage.  It  has  been 
stated  that  the  demand,  all  told,  is  for  about  500  tons  annually. 
Should  larger  and  more  constant  sources  of  supply  be  found,  it  is 
probable  its  use  could  be  considerably  extended.  According  to 
Nordenskiold,  ^50,000  worth  of  uranium  minerals  are  consumed 
every  year,  the  various  salts  produced  being  used  in  porcelain  and 
glass  manufacture,  in  photography,  and  as  chemical  reagents.  The 
material  has  of  late — in  the  public  mind  at  least — possessed  an 
almost  sensational  interest  in  connection  with  the  discovery  of  its 
radio-active  properties,  and  the  new  elements  radium  and  polonium, 
of  which  it  forms  the  chief  commercial  source. 


2.    CARNOTITE 

The  name  carnotite  was  given  in  1899  by  MM.  E.  Cumengc 
and  C.  Friedel  to  a  beautiful  canary-yellow  ocherous  pigment  which 
was  found  impregnating  a  siliceous  sandstone  in  Montrose  County, 
Colorado.  Material  from  the  same  and  other  sources  has  since  been 
examined  by  Dr.  W.  F.  Hillebrand,1  whose  results  show  the  material 
to  be  not  a  simple  mineral,  but  a  mixture  made  up  in  large  part  of 
an  impure  uranyl-vanadate  of  potash  and  the  alkaline  earths.  The 

1  American  Journal  of  Science,  X,  August,  1900. 


URANATES. 


333 


composition  of  material  from  (i)  the  Copper  Prince  claim,  Roe 
Creek,  and  (2)  the  Yellow  Boy  claim,  La  Sal  Creek,  and  in  Mon- 
trose  County,  as  shown  by  Hillebrand's  analyses,  is  given  below: 

ANALYSES    OF    CARNOTITE   FROM    COLORADO. 


I. 

I 

I. 

A. 

B. 

C. 

A. 

B. 

Insoluble 

7.10 

8.34 

I9.OO 

10.33 

UO                         .    . 

^4.80 

S2.2< 

47.42 

554.00 

S2.28 

vo 

18.40 

i8.« 

1^.76 

18.0? 

i7.=;o 

P  O 

.80 

,7C 

.40 

.ON 

Trace. 

As  O 

Trace. 

.2^ 

None. 

None. 

None. 

"TXl  

A1O 

.00 

? 

.08 

.20 

? 

Fe  O 

.21 

1-77 

-72 

.42 

3-^6 

*  C2^3  

CaO  

7.74 

2.85 

2-S7 

1.86 

1.85 

SrO 

O2 

?5 

? 

Trace. 

Trace. 

BaO 

QO 

.72 

6< 

2.83 

•?.2I 

MgO 

22 

2O 

24 

.14 

.17 

KO 

6.S2 

6.73 

6.0 

"v4.6 

tc.n 

Na,O   

.14 

.OQ 

.07 

•  I"? 

.02? 

LLO  

Trace. 

?9 

> 

Trace. 

? 

H  O,  ios°  

2.4^ 

2.<Q 

1.8? 

3.16 

(  4.C2 

H0O,  3=;o0.. 

2.  II 

3.06 

2.70 

2.21 

a  <  ^  •> 
i  7.40 

PbO  

.1? 

.2< 

.18 

.07 

CuO             

.it; 

.20 

.22 

Trace. 

so         

None. 

.12 

.18 

None. 

MoO          

.18 

.27 

.18 

.0? 

SiO 

•  i  ^ 

.06 

•13 

.20 

TiO 

•  OT. 

.IO 

? 

? 

CO 

,<6 

.-2-7 

None. 

None. 

-^2  m  • 

Total 

08  46 

O8  84 

oo  01 

OQ  2^ 

a  Total  H2O  in  ore. 

Occurrence. — As  above  stated,  the  material  is  found  in  sandstone. 
F.  L.  Ransome  l  describes  the  La  Sal  Creek  deposit  as  occurring  in 
irregular  bunchy  pockets,  the  ore  bodies  being  usually  flat-lying 
streaks  but  a  few  inches  thick  grading  both  above  and  below  into 
the  common  light-buff  sandstone,  the  carnotite  gradually  dying  out 
until  the  rock  shows  no  trace  of  the  mineral.  At  Roe  Creek  the 
carnotite  occurs  in  a  nearly  horizontal  sandstone  which  has  been 
cut  by  a  fault-plane  dipping  about  75°  N.  The  material  is  here 
found  in  the  hanging- wall  of  the  fissure  in  the  form  of  small,  irregular 
branches  in  a  loose  mass  of  crushed  sandstone  and  also  as  an  im- 


1  American  Journal  of  Science,  X,  August,  1900. 


334  THE   NON-METALLIC  MINERALS. 

pregnation  of  some  of  the  finer  portions  of  the  bed,  the  impregnation, 
as  at  La  Sal  Creek,  taking  place  mainly  along  the  bedding  planes. 
In  all  cases  thus  far  reported  the  deposits  are  superficial  and  appar- 
ently result  "  from  a  local  concentration  of  material  already  existing 
in  the  sandstone  .  .  .  under  conditions  determined  by  proximity 
to  the  surface." 

Carnotite  is  also  found  impregnating  the  Dakota  (Cretaceous) 
sandstone  of  Rio  Blanco  County  in  the  same  State. 

Uses. — The  material  has  been  used  to  some  extent  as  a  source 
of  uranium  and  vanadium  salts. 


XII.  SULPHATES, 
i.  BARITE;  HEAVY  SPAR. 

Composition. — BaSO4,  =  sulphur  trioxide,  34.3  per  cent;  baryta, 
65.7  per  cent;  specific  gravity,  4.3  to  4.6;  hardness,  2.5  to  3.5. 

The  sulphate  of  barium  to  which  the  mineralogical  name  of 
barite  is  given  occurs,  as  a  rule,  in  the  form  of  a  white,  translucent  to 
transparent,  coarsely  crystalline  mineral,  about  as  hard  as  common 
calcite,  but  from  which  it  may  be  readily  distinguished  by  its  great 
weight  and  its  not  effervescing  when  treated  with  acid.  A  common 
form  of  the  mineral  is  that  of  an  aggregate  of  straight  or  somewhat 
curved  plates,  separating  readily  from  one  another  when  struck  with  a 
hammer,  and  cleaving  readily  into  rhomboidal  forms  much  like 
calcite.  It  is  also  found  in  globular  and  nodular  concretions,  stal- 
actitic  and  stalagmitic,  granular,  compact,  and  earthy  masses,  and 
in  single  and  clustered  broad  and  stout  crystals.  In  nature  the 
material  is  rarely  pure,  but  nearly  always  contaminated  with  other 
elements,  as  noted  in  the  following  analyses  of  samples  from  Fulton, 
Blair,  and  Franklin  counties,  Pennsylvania.1 

1  Pennsylvania  Second  Geological  Survey,  Chemical  Analyses,  pp.  568,  569. 


SULPHATES. 


335 


Constituents. 

Fulton  County. 

Blair 
County. 

Franklin  County. 

Sulphate  of  barium.        

95.22 
0.38 
0.05 

o-59 
0.18 
0.65 
0.23 
2-45 

96.91 
0.31 
None. 
Trace. 
Trace. 
None. 
0.08 
2-35 

97.08 
0.76 
None. 
None. 
Trace. 
None. 
0.32 
1.74 

95-91 
0.24 
None. 
0.17 

O.II 

None. 
0.09 

2.80 

98.65 
0.14 
None. 
Trace. 
Trace. 
None. 

O.2O 

i.  n 

Oxides  of  iron  and  aluminum. 
Oxide  of  manganese  

^Magnesia                   

Carbonic  acid       .    .    ........ 

Water                     

Silica                     

Total               

99-75 

99  -65 

99.90 

99-32 

100.10 

Occurrence. — The  mineral  is  a  common  accompaniment  of  me- 
tallic ores,  but  as  such  has  not  proven  of  any  value  commercially. 
Such  deposits  as  have  been  worked  for  the  mineral  itself  are,  as  a 
rule,  pockety  or  lenticular  masses  mainly  in  limestone  and  following 
the  dip  and  strike  of  the  rocks  with  which  they  are  associated.  In 
Washington  County,  southwest  Virginia,  the  mineral  occurs  in 
coarsely  cleavable  masses  ;n  certain  beds  of  the  Cambrian  limestone, 
filling  irregular  fractures  or  at  times  replacing  the  limestone  itself. 
In  Tazewell  County,  this  same  State,  it  is  described  as  occurring 
in  a  series  of  lenticular  pockets  having  a  general  northeast-southwest 
strike,  and  dipping  from  20°  to  30°  toward  the  east.  The  general 
width  of  this  series  of  pockets  is  given1  as  from  100  to  200  or  more  feet 
and  occurring  over  an  area  some  4  miles  in  length.  The  pockets 
are  at  times  quite  distinct  from  one  another,  or  again  may  be  connected, 
by  a  thin  seam  of  barite.  In  Madison  and  Gaston  counties,  North 
Carolina,  the  material  is  found  in  a  seam  or  vein  from  3  to  6  feet  in 
width  in  a  decomposed  schist. 

In  Missouri  barite  occurs  in  cavities  in  a  dolomite  of  Ordovician 
age,  the  cavities,  according  to  A.  A.  Steel,2  being  due  in  part  to  a 
shattering  which  he  regards  as  incidental  to  dolomitization,  and  in 
part  to  fissuring  and  faulting,  in  either  case  being  subsequently 


1  J.  H.  Pratt,  Mineral  Resources  of  the  United  States,  1901,  p.  915. 

2  Bulletin  American  Institute  of  Mining  Engineers,  No.  38,  February,  1910. 


336 


THE  NON-METALLIC  MINERALS. 


enlarged  by  solution.  The  barite  filling  was  probably  a  result  of  a 
process  of  concentration  by  leaching  from  the  country  rock,  though 
its  primary  source  was  undoubtedly  the  pre-existing  igneous  rocks 
forming  the  neighboring  ancient  land  areas.  The  chief  barite-pro- 
ducing  ground  is  at  present  eastern  Washington  County,  the  mineral 
being  mined  in  nodular  masses  from  the  residual  clay.  The  average 

yield,  mainly  from  open 
cuts  and  trenches,  is 
about  600  tons  per  acre. 
Where  mined  to  a  depth 
of  8  feet,  yields  as  high 
as  2,500  to  4,000  tons 
per  acre  have  been  re- 
ported. 

The  principal  local- 
ities in  the  United  States 
where  barite  has  been 
mined  on  a  commercial 
scale  are  in  Connecticut, 


FIG.  50. — Ideal  section  of  Bennett  Barite  Mine, 

Pittsylvania  County,  Virginia. 
[After  Watson,  Mineral  Resources  of  Virginia.] 


Virginia,  North  Carolina, 
Tennessee,  and  Missouri, 
though  the  first-named  State  has  ceased  to  be  a  producer.  The  min- 
ing is  almost  wholly  from  open  cuts,  the  cheapness  of  the  material 
militating  against  the  expense  of  deep  mining.  When  occurring 
in  limestone  the  material  is  found  superficially  in  loose  nodules 
and  fragments  embedded  in  the  residual  clay  resulting  from  its 
decomposition.  In  Missouri  and  Tennessee  it  is  often  associated 
with  a  small  amount  of  galena. 

Preparation  and  uses. — The  mineral  is  washed  and  ground  like 
grain  between  millstones  and  used  as  an  adulterant  for  white  lead 
or  to  give  weight  and  body  to  certain  kinds  of  cloth  and  paper.  Con- 
siderable quantities  are  utilized  in  the  preparation  of  barium  salts 
for  various  chemical  purposes. 

According  to  a  writer  in  the  Mineral  Resources  of  the  United 
States  for  1885,  the  "  floated  "  or  "  cream-floated  "  barite  used  as 
paint  is  prepared  as  follows:  The  crude  mineral  as  mined  is  first 


SULPHATES. 


337 


sorted  by  hand  and  cleaned,  after  which  it  is  crushed  into  pieces 
about  the  size  of  the  tip  of  one's  finger.  Next  it  is  refined  by  boiling 
in  dilute  sulphuric  acid  until  all  the  impurities  are  removed,  when  it 
is  washed  by  boiling  in  distilled  water  and  dried  by  steam.  It  is  then 
ground  to  flour,  mixed  with  water,  and  run  through  troughs  or  sluice- 
ways into  receiving  vats,  whence  it  is  taken,  again  dried  by  steam, 
and  barreled.  The  crude  material  is  worth  only  about  $3.50  per 
ton. 

2.  GYPSUM. 

Composition. — CaSO4+2H2O,  =  sulphur  trioxide,  46.6  per  cent; 
lime,  32.5  per  cent;  water,  20.9  per  cent.  The  natural  mineral  is 
often  quite  impure  through  the  presence  of  organic,  ferruginous, 
and  aluminous  matter,  together  with  small  quantities  of  the  carbon- 
ates of  lime  and  magnesia  (see  analysis,  below).  Specific  gravity, 
2.3;  hardness,  1.5,  to  2.  Color,  usually  white  or  gray,  but  brown, 
black,  and  red  through  impurities.  The  softness  of  the  mineral,  which 
is  such  that  it  can  be  easily  cut  with  a  knife,  or  even  by  the  thumb 
nail,  is  one  of  its  most  marked  characteristics.  Three  principal 
varieties  are  recognized,  (i)  the  crystallized,  foliated,  transparent 
variety,  selenite,  (2)  the  fine  fibrous,  often  opalescent  variety,- 
satin  spar,  and  (3)  the  common  massive,  finely  granular  variety, 
gypsum.  When  of  a  white  color  and  sufficiently  compact  for 
small  statues  and  other  ornamental  works,  it  is  known  as  alabaster, 
though  this  name  has  unfortunately  become  confounded  with  the 
calcareous  rock  travertine  and  stalagmite.1 

The  following  is  an  analysis  of  a  commercial  gypsum  from  Ottawa 
County,  Ohio,  as  given  by  Professor  Orton:2 


Constituents. 

Per  Cent. 

Lime 

32    5  2 

Sulphuric  acid 

A  C       f  6 

Water 

2O    IA 

IMagnesia 

o  ^6 

Alumina 

o  16 

Insoluble  residue 

o  68 

Total     .   . 

oo  62 

1  See  The  Onyx  Marbles,  their  Origin,  Uses,  etc.,  Report  of  the  U.  S.  National 
Museum,  1893,  PP-  539-5^5. 

2  Geology  of  Ohio,  VI,  1888,  p.  700. 


33 8  THE  NON-METALLIC  MINERALS. 

Origin. — Gypsum  in  considerable  quantities  occurs  associated 
only  with  stratified  rocks,  and  is  regarded  mainly  as  a  chemical  de- 
posit resulting  from  the  evaporation  of  waters  of  inland  seas  and 
lakes;  it  may  also  originate  through  the  decomposition  of  sulphides 
and  the  action  of  the  resultant  sulphuric  acid  upon  limestone;  through 
the  mutual  decomposition  of  the  carbonate  of  lime  (limestone)  and 
the  sulphates  of  iron,  copper,  and  other  metals;  through  the  hydra- 
tion  of  anhydrite  and  through  the  action  of  sulphurous  vapors  and 
solutions  from  volcanoes  upon  the  rocks  with  which  they  come  in 
contact.  According  to  Dana,1  the  gypsum  deposits  in  western  New 
York  do  not  form  continuous  layers  in  the  strata,  but  lie  in  embedded, 
sometimes  nodular  masses.  In  all  such  cases,  this  authority  says, 
the  gypsum  was  formed  after  the  beds  were  deposited,  and  in  this 
particular  instance  are  the  product  of  the  action  of  sulphuric  acid 
from  springs  upon  the  limestone.  "This  sulphuric  acid,  acting  on 
limestone  (carbonate  of  lime),  drives  off  its  carbonic  acid  and  makes 
sulphate  of  lime,  or  gypsum ;  and  this  is  the  true  theory  of  its  forma- 
tion in  New  York."  Dr.  F.  J.  H.  Merrill,  however,  regards  a  por- 
tion at  least  of  the  New  York  beds  as  a  product  of  direct  chemical 
precipitation  from  sea  water.2 

The  gypsum  of  northern  Ohio  is  regarded  by  Professors  New- 
berry  and  Orton  as  a  deposit  from  the  evaporation  of  landlocked 
seas,  as  was  also  the  rock  salt  which  overlies  it.  By  this  same  proc- 
ess must  have  originated  a  large  share  of  the  more  recent  gypsum 
deposits  of  the  Western  States. 

Geological  age  and  mode  o]  occurrence. — As  may  be  readily  inferred 
from  the  above,  beds  of  gypsum  have  formed  at  many  periods  of  the 
earth's  history,  and  are  still  forming  wherever  proper  conditions 
exist.  The  deposits  of  New  York  State  occur  in  a  belt  extending 
eastward  from  Cayuga  Lake  and  in  beds  belonging  to  the  Salina 
period  of  the  Upper  Silurian  Age.  The  rock  is  often  earthy  and 
impure,  and  is  used  nearly  altogether  for  land  plaster.  It  is  asso- 
ciated with  dark,  nearly  black,  limestones  and  shales  and  beds  of 
rock  salt.  In  southwest  Virginia,  along  the  Holston  River,  are  also 

1  Manual  of  Geology,  p.  234. 

3  Bulletin  No.  n  of  the  New  York  State  Museum,  April,  1893. 


-. 


PLATE  XXXI. 

Gypsum  Quarry,  Fort  Dodge,  Iowa. 
[From  photograph  by  Iowa  Geological  Survey.] 

[Facing  page  338.] 


SULPHATES.  339 

beds  of  gypsum  associated  with  salt  and  referred  by  Dana  to  this 
same  horizon.  The  rock  is  mined  at  Saltville  in  Washington  County 
from  underground  pits,  and  is  used  mainly  for  fertilizing. 

Gypsum  deposits  of  varying  thickness  and  occurring  at  various 
depths  below  the  surface  are  found  continuous  over  thousands  of 
square  miles  in  northern  Ohio,  but  are  at  present  worked  only  in 
Ottawa  County  at  a  station  on  the  Lake  Shore  and  Michigan  South- 
ern Railway  which  bears  the  appropriate  name  of  Gypsum.  The 
associated  rocks  are  Lower  Helderberg  limestones  and  shales,  and 
the  beds,  which  vary  from  3  to  7  feet  in  thickness,  are  found  at  all 
depths  up  to  200  or  300  feet. 

The  following  is  a  section  of  the  Ottawa  County  beds  as  given  by 
Orton : 1 

Feet. 

Drift  clays 1 2  to  14 

No.  i.  Gray  rock,  carrying  land  plaster 5 

Blue  shale «J 

No.  2.  Bowlder  bed  carrying  gypsum  in  separate  masses 

embedded  in  shaly  limestone 5 

Blue  limestone,  in  thin  and  even  courses i 

Mo.  3.  Main  plaster  bed 7 

Gray  limestone  in  courses '. i 

No.  4.  Lowest  plaster  bed,  variable 3  to  5 

Mixed  limestone  and  plaster,  bottom  of  quarry. 

Sections  like  the  above  are  stated  to  be  capable  of  yielding  50,000 
tons  of  plaster  an  acre. 

The  purest  gypsum  of  the  region  occurs  in  No.  2,  the  bowlder 
bed,  as  given  above.  It  consists  of  calcareous  shales  through  which 
are  scattered  concretionary  balls  of  gypsum  varying  in  diameter  from 
6  to  24  inches.  This  pure  variety  is  used  mainly  for  terra  alba;  about 
40  per  cent  of  the  total  product  has  in  years  past  been  calcined  for 
use  as  stucco  or  plaster  of  Paris  and  60  per  cent  for  land  plaster. 

At  Fort  Dodge,  in  Iowa,  is  a  deposit  of  quite  pure,  light-gray, 
regularly  bedded  gypsum,  resting  unconformably  upon  St.  Louis 
limestone  and  lower  coal  strata  and  overlain  by  drift.  It  is  supposed 

1  Geological  Survey  of  Ohio.     Economic  Geology,  VI,  1888,  p.  698. 


340  THE  NON-METALLIC  MINERALS. 

to  cover  an  area  of  some  25  square  miles.  The  material  was  at  one 
time  used  for  building  purposes,  but  proved  too  soft1  and  is  now 
used  mainly  for  land  plaster.  (See  Hate  XXXI.) 

There  are  large  deposits  of  gypsum  in  Michigan,  the  most  exten- 
sive, so  far  as  explored,  being  near  Grand  Rapids,  Kent  County,  in 
the  western  part  of  the  State,  and  at  Alabaster  Point,  in  losco  County, 
on  the  eastern  margin  of  the  State.  At  both  localities  there  is  a 
succession  of  beds  beginning  at  or  near  the  surface  and  aggregating 
many  feet  in  depth.  The  beds  are  regarded  as  of  Carboniferous 
age.  The  following  section  shows  the  number  and  thickness  of  the 
beds  thus  far  discovered: 

Feet. 

Earth  stripping 20 

Gypsum 8 

Soft  shale,  slate. i 

Gypsum 12 

Shale  or  clay  slate 7 

Gypsum 6  J 

do 8} 

Slate,  shale 3  J 

Gypsum 1 2 J 

Shale  or  clay  slate i  J 

Gypsum 9^ 

Shale,  clay  slate 8 

Total 98 

In  Kansas  are  notable  deposits  of  gypsum  associated  with  rocks 
regarded  by  Haworth2  as  of  Permian  age.  The  most  important 
beds  so  far  as  now  known  are  in  Marshall  and  Barber  counties. 
Southwest  of  Medicine  Lodge  in  the  last-named  county  the  material 
occurs  in  beds  from  20  to  30  feet  in  thickness  and  covering  many 
square  miles  of  territory. 

West  of  the  front  range  of  the  Rocky  Mountains  are  many  impor- 
tant beds  of  gypsum,  but  which  have  as  yet  been  but  little  exploited 

1  Stones  for  Building  and  Decoration,  ad  ed.,  1897,  p.  76. 

2  Mineral  Resources  of  Kansas,  1897. 


SULPHATES.  34* 

owing  to  cost  of  transportation,  there  being  but  little  local  demand. 
These  beds  so  far  as  yet  worked  are  mostly  of  more  recent  origin 
than  those  in  the  eastern  United  States,  many  being  of  Tertiary  or 
even  Quarternary  Age. 

Near  Fillmore,  Utah,  are  deposits  of  gypseous  sand  formed  by  the 
winds  blowing  up  from  the  dry  beds  of  playa  lakes  the  minute  crys- 
tals deposited  by  evaporation.  The  material  thus  blown  together 
forms  veritable  dunes  from  which  the  material  may  be  obtained  by 
merely  shoveling.  Prof.  I.  C.  Russell  has  estimated  these  dunes  to 
contain  not  less  than  450,000  tons  of  gypsum. 

Important  deposits  of  gypsum  also  occur  in  Colorado,  South 
Dakota,  Wyoming,  California,  New  Mexico,  Oklahoma,  and  Texas. 

Gypsum  is  a  very  abundant  mineral  in  New  Brunswick,  the 
deposits  being  numerous,  large,  and  in  general  of  great  purity.  They 
occur  in  all  parts  of  the  Lower  Carboniferous  district  in  Kings, 
Albert,  Westmoreland,  and  Victoria,  especially  in  the  vicinity  of 
Sussex,  in  Upham,  on  the  North  River  in  Westmoreland,  at  Martin 
Head  on  the  bay  shore,  on  the  Tobique  River  in  cliffs  over  100  feet 
high,  and  about  the  Albert  Mines.  At  the  last-named  locality  the 
mineral  has  been  extensively  quarried  from  beds  about  60  feet  in 
thickness.1  The  mineral  is  usually  met  with  in  very  irregular  masses, 
associated  with  red  marls,  sandstones,  and  limestones,  and  varies 
much  in  character.  At  Hillsborough  considerable  masses  of  very 
beautiful  snow-white  gypsum  or  alabaster  are  also  met  with,  and  a 
little  selenite.  At  Petitcodiac  the  deposit  has  a  breadth  of  about 
40  rods  and  total  length  of  about  i  mile.  The  whole  bed  is  fibrous 
and  highly  crystalline  and  traversed  through  its  entire  extent  by  a 
vein  of  nearly  pure  selenite,  8  feet  wide.  The  rock  on  the  Tobique 
River,  which  rises  in  bluffs  along  the  stream  some  30  miles  above 

1  Dawson's  Acadian  Geology,  p.  249. 


342  THE  NON-METALLIC  MINERALS. 

its  mouth,  is  mostly  soft,  granular  or  fibrous,  and  of  a  more  decidedly 
reddish  color  than  in  the  other  localities. 

Important  beds  of  gypsum  belonging  to  the  same  geological  hori- 
zon likewise  occur  in  Nova  Scotia,  particularly  at  Went  worth  and 
Montague  in  Hants  County,  at  Oxford,  River  Philip,  Plaster  Cove, 
Wallace  Harbor,  and  Bras  d'Or  Lake,  Cape  Breton.  At  Wentworth 
there  are  stated  to  be  "  cliffs  of  solid  snowy  gypsum  from  100  to  200 
feet  in  height." 

Gypsum  deposits  occur  in  the  Onondaga  formations  of  Ontario, 
Canada,  and  are  exploited  along  the  Grand  River  between  Cayuga 
and  Paris.  The  mineral  here  occurs  in  lenticular  masses  varying 
from  a  few  yards  to  a  quarter  of  a  mile  in  horizontal  diameter  and 
from  3  to  7  feet  in  thickness. 

The  foreign  sources  of  gypsum  are  almost  too  numerous  to  men- 
tion. Important  beds  occur  in  Lincolnshire  and  Derbyshire,  Eng- 
land; near  Paris,  France;  in  Spain,  Italy,  Germany,  Austria,  and 
Switzerland.  The  Paris  beds  are  of  Tertiary  Age,  and  the  mineral 
carries  some  10  to  20  per  cent  of  carbonate  of  lime,  together  with 
silica  in  a  soluble  form.  The  presence  of  these  constituents  is  stated 
to  cause  the  plaster  to  set  much  harder,  permitting  it,  therefore,  to 
be  used  for  external  work.  The  Italian  gypsum  is  often  of  great 
purity.  The  finest  alabaster  is  stated  to  come  from  the  Val  di  Marmo- 
lago,  near  Castellina. 

Uses. — These  have  been  already,  in  part,  noted.  The  principal 
use  of  the  ordinary  massive  varieties  is  for  fertilizers  (land  plaster), 
and  in  the  manufacture  of  plaster  of  Paris,  or  stucco.  The  New 
York  material  is  also  used  in  the  preparation  of  the  so-called  adamant 
cement  for  wall  plaster. 

As  above  noted,  gypsum  is  but  little  used  for  building  purposes, 
being  too  soft.  Several  residences,  a  railway  station,  and  other 
minor  structures  are,  however,  stated  to  have  been  built  of  this  stone 
at  Fort  Dodge,  in  Iowa.  The  variety  satin  spar  is  sometimes  used 
for  small  ornamentations,  but  it  is  only  the  snow-white  variety  (ala- 
baster) that  is  of  any  economic  importance  as  an  ornamental  stone. 
The  main  use  of  alabaster  is  for  small  statues,  vases,  fonts,  and  small 
columns;  it  is  too  soft  for  exposed  positions  where  subjected  to 
much  wear.  At  present  there  are  not  known  any  deposits  of  ala- 


SULPHATES.  343 

baster  within  the  limits  of  the  United  States  which  are  of  sufficient 
purity  and  extent  to  be  of  commercial  value.  A  large  share  of  the 
alabaster  statuettes  now  on  our  markets  are  of  Italian  make  as  well  as 
of  Italian  materials. 

In  preparing  the  gypsum  for  market  the  stone  is  first  broken  in  a 
crusher  into  pieces  of  the  size  of  a  hickory  nut,  after  which  it  is  ground 
between  millstones  (French  buhrstones)  to  a  proper  degree  of  fine- 
ness and  then  put  up  in  bags  or  barrels,  if  designed  for  land  plaster; 
if  for  stucco  it  is 'calcined  after  being  ground.  This  process  is  in 
Michigan  carried  on  in  large  kettles  some  8  feet  in  diameter,  and 
capable  of  holding  about  14  barrels  at  a  charge.  The  powder  is 
heated  until  all  the  included  water  is  driven  off,  being  subjected  to 
constant  stirring  in  the  mean  time,  and  is  then  drawn  off  through 
the  bottom  of  the  kettles  and  conveyed  by  carrying  belts  and  spouts 
to  the  packing  room.1 

Under  the  name  of  " terra  alba"  (white  earth)  ground  gypsum 
is  used  as  an  adulterant  in  cheap  paints. 

The  commercial  value  of  gypsum  depends  mainly  on  accessibility 
to  market.  In  1899  the  ground  material  was  quoted  at  $2.00  a 
ton  in  New  York.  In  Michigan  the  average  price  of  crude  material 
has  been  some  $1.25  a  ton,  and  for  calcined  plaster  (plaster  of  Paris) 
$3.00  to  $5.00  a  ton.  During  1908  the  domestic  production  of 
crude  gypsum  amounted  to  1,721,289,  tons,  valued  at  $4,138,560. 

3.    CELESTITE. 

Composition. — Sulphate  of  strontium,  SrSO4,  =  sulphur  trioxide, 
43.6  per  cent;  strontia,  56.4  per  cent.  Hardness,  3  to  3.5;  specific 
gravity,  3.99;  color,  white,  often  bluish,  transparent  to  translucent. 
Differs  from  the  carbonate  (strontianite)  by  being  insoluble  in  acids, 
but  gives  the  characteristic  red  color  to  the  blowpipe  flame. 

According  to  Dana  the  mineral  occurs  usually  associated  with 
limestones  or  sandstones  of  Silurian  or  Devonian,  Jurassic,  and 
other  geological  formations,  occasionally  with  metalliferous  ores.  It 
also  occurs  in  beds  of  rock  salt,  gypsum,  and  clay,  and  is  abundantly 

1  See  Mineral  Statistics  of  Michigan,  1881,  for  details  of  plaster  work  of  that  State. 


344  THE  NON-METALLIC  MINERALS. 

associated  with  the  sulphur  deposits  of  Sicily.  The  principal  locali- 
ties in  the  United  States  are  in  the  limestones  of  Drummond  Island, 
Lake  Huron;  Put-in-Bay,  Lake  Erie;  Kingston,  Ontario,  in  crystal- 
line masses,  and  in  radiating  fibrous  masses  in  the  Laurentian  forma- 
tions about  Renfrew.  Large  crystals  of  a  red  color  are  also  found 
in  Brown  County,  Kansas,  and  at  Lampasas  and  near  Austin, 
Texas.  Near  Bells  Mills,  Blair  County,  Pennsylvania,  the  mineral 
occurs  in  lens-shaped  masses  between  the  bottommost  beds  of  the 
Lower  Helderberg  limestone.  On  South  Bass  Island,  in  Put-in- 
Bay,  Lake  Erie,  the  mineral  occurs  frequently  in  the  form  of  beautiful 
crystals  of  all  sizes  up  to  100  pounds  in  weight,  transparent  to  trans- 
lucent, and  sometimes  of  a  fine  blue  color,  lining  the  walls  and  floor 
of  limestone  caverns. 

The  Texas  celestite  is  described1  as  occurring  in  rounded  cavities 
varying  in  size  up  to  18  inches  in  diameter  in  certain  zones  of  Creta- 
ceous limestone.  The  cavities  are  sometimes  fairly  well  filled  by  the 
mineral,  but  in  most  instances  a  portion  has  been  removed  in  solu- 
tion by  percolating  waters.  It  is  estimated  that  the  average  amount 
of  the  celestite  in  the  limestone  does  not  exceed  5  per  cent. 

Uses. — Celestite  is  used  in  the  preparation  of  nitrate  of  strontia 
employed  in  fireworks,  its  value  for  this  purpose  being  due  to  the 
fine  crimson  color  it  imparts  to  the  flame.  Other  strontium  salts, 
prepared  either  from  celestite  or  strontianite,  are  used  in  refining 
beet  sugar.  Small  quantities  are  utilized  in  medicine.  The  demand 
for  the  material  is  very  small,  and  the  annual  product  in  the  United 
States  limited  to  40  tons  in  1901. 

4.    MIRABILITE  ;    GLAUBER    SALT. 

This  is  a  hydrous  sodium  sulphate,  Na2SO4-f  ioH2O,  =  sulphur 
trioxide,  24.8  per  cent;  soda,  19.3  per  cent;  water,  55.9  per  cent. 
In  its  pure  state  white,  transparent  to  opaque;  hardness,  1.5  to  2; 
specific  gravity,  1.48.  Readily  soluble  in  water,  taste  cool,  then 
saline  and  bitter. 

Occurrence. — Aside  from  its  occurrence  in  soda  lakes  associated 
with  other  salts  as  described  later  this  sulphate  is  of  common  occur- 

1  F.  L.  Hess,  Engineering  and  Mining  Journal,  June  17,  1909. 


SULPHATES. 


345 


rence  as  an  efflorescence  on  limestones,  and  in  protected  places,  as 
in  Mammoth  Cave,  Kentucky,  may  accumulate  in  considerable 
quantities,  though  not  sufficient  to  be  of  economic  value.  Salt  Lake, 
Utah,  contains  a  proportionately  large  amount  of  this  sulphate, 
which  during  the  winter  months  is  precipitated  to  the  bottom,  whence 
it  is  not  infrequently  thrown  upon  the  shore  by  waves. 

According  to  Prof.  J.  E.  Talmage,1  when  the  temperature 
falls  to  a  certain  point,  the  lake  water  assumes  an  opalescent  appear- 
ance from  the  separation  of  the  sulphate.  This  sinks  as  a  crystalline 
precipitate  and  much  is  carried  by  the  waves  upon  the  beach  and 
there  deposited.  Under  favorable  circumstances  the  shores  become 
covered  to  a  depth  of  several  feet  with  crystallized  mirabilite.  The 
substance  must  be  gathered,  if  at  all,  soon  after  the  deposit  first 
appears;  as,  if  the  water  once  rises  above  the  critical  temperature, 
the  whole  deposit  is  taken  again  into  solution.  This  change  is  very 
rapid,  a  single  day  being  oftentimes  sufficient  to  effect  the  entire 
disappearance  of  all  the  deposit  within  reach  of  the  waves.  Warned 
by  these  circumstances,  the  collectors  heap  the  substance  on  the 
shores  above  the  lap  of  the  waters,  in  which  situation  it  is  compara- 
tively secure  until  needed.  To  a  slight  depth  the  mirabilite  efflo- 
resces, but  within  the  piles  the  hydrous  crystalline  condition  is  main- 
tained. The  sulphate  thus  lavishly  supplied  is  of  a  fair  degree 
of  purity,  as  will  be  seen  from  the  following  analyses  of  two  samples 
taken  from  opposite  shores  of  the  lake : 


Constituents. 

Per  Cent. 

Per  Cent. 

Water 

r  s  O7O 

c  c  760 

Sodium  sulphate  (Na2SO4)  
Sodium  chloride  (NaC"!) 

43.060 

o  600 

42.325 

o  6^1 

Calcium  sulphate  (CaSO4)  
Magnesium  sulphate  (MgSO4). 
Insoluble  

0.407 
0.025 
O.7OO 

0.267 
0.018 

O.7C6 

Total 

oo  06  1 

OO  7C7 

yy'/  01 

Some  14  miles  southwest  of  Laramie,  in  Albany  County,  Wyo- 
ming, there  exist  deposits  of  sulphate  of  soda,  such  as  are  locally 

1  Science,  XIV,  1889,  p.  446. 


346 


THE  NON-METALLIC  MINERALS. 


known  as  "lakes."  The  deposits  in  question  comprise  three  of  these 
lakes  lying  within  a  stone's  throw  of  one  another.  They  have  a 
total  area  of  about  65  acres,  the  local  names  of  the  three  being  the 
Big  Lake,  the  Track  Lake,  and  the  Red  Lake.  Being  the  property 
of  the  Union  Pacific  Railroad  Company,  they  are  generally  known 
as  the  Union  Pacific  Lakes. 

In  these  lakes  the  sulphate  occurs  in  two  bodies  or  layers.  The 
lower  part,  constituting  the  great  bulk  of  the  deposit,  is  a  mass  of 
crystals  of  a  faint  greenish  color  mixed  with  a  considerable  amount 
of  black,  slimy  mud.  It  is  known  as  the  "  solid  soda,"  of  which  an 
analysis  is  given  below.1 


Constituents. 

Anhy- 
drous. 

Crystal- 
lized. 

NaSO 

36.00 

81.63 

CaSO4 

1.4? 

1.82 

M>C1                                .  '  

O.77 

1.64 

Nad.              

O.2I 

O.2I 

Insoluble  residue  (at  100°  C.) 

38-B 

8S-30 
13.86 

99.16 

Total  chloride  calculated  as  NaCl  equals  1.16  per  cent.  This,  calculated  on  100 
parts  anhydrous  Na.,SO4,  equals  3.22  per  cent  NaCl. 

This  solid  soda  is  stated  to  have  a  depth  of  some  20  or  30  feet. 

Above  this  occurs  a  superficial  layer  of  pure  white  crystallized 
material.  This  is  formed  by  solution  in  water  of  the  upper  part  of 
the  lower  bed,  the  crystals  being  deposited  by  evaporation  or  cool- 
ing. A  little  rain  in  the  spring  and  autumn  furnishes  this  water, 
as  do  also  innumerable  small,  sluggishly  flowing  springs  present 
in  all  the  lakes.  On  account  or  the  aridity  of  the  region  the  surface 
is  generally  dry,  or  nearly  so,  and  in  midsummer  the  white  clouds 
of  efflorescent  sulphate  that  are  whirled  up  by  the  ever-blowing 
winds  can  be  seen  for  miles.  Even  when  there  is  a  little  water  present 
there  is  no  difficulty  in  gathering  the  crystals  by  the  train  load. 
The  layer  of  this  white  sulphate  is  from  3  to  12  inches  in  thickness. 
When  the  crystals  are  removed  the  part  laid  bare  is  soon  replenished 
by  a  new  crop. 

The  following  is  an  analysis  of  the  purest  of  the  white  sulphate 
of  soda,  calculated  upon  an  anhydrous  basis: 

1  Jour.  Franklin  Inst.,  1893,  p.  52. 


SULPHATES. 


347 


Constituents. 

Per  Cent. 

Na,S(X 

00   73 

MgCl,     . 

o   26 

Insoluble  

Trace 

99-99 

Below  is  given  an  analysis  of  the  water  of  the  Track  lake : 
Density  =  14 \     Tw.     (=1.0725    specific    gravity).     Ten 
centimeters  contain: 


cubic 


Constituents. 

Grams.      Per  Cent. 

Na,SO4.  . 

0.7^63  =    02.23 

CaSO4 

O   0146  —       I    7O 

MeSO, 

o  0070  —      o  8<\ 

MeCU 

o  0300  —      3  66 

Na2B4O7 

o  0121  —      i  47 

Total  solids  

0.8200     100.00 

Total  solids  by  evaporation  . 

0.8240 

Other  soda  deposits  occur  in  Carbon  and  Natrona  counties,  and 
still  others  are  reported  in  Fremont,  Johnson,  and  Sweetwater 
counties. 

It  has  been  stated1  that  glauber  salts  has  been  found  on  the  bot- 
tom of  Bay  of  Kara  Bougas,  an  inlet  of  the  Caspian  Sea,  in  deposits 
sometimes  a  foot  in  thickness. 

5.    GLAUBERITE. 

Composition. — Sodium  and  calcium  sulphate.  Na2SO4.CaSO4,  = 
sulphur  trioxide,  57.6  per  cent;  lime,  20.1  per  cent;  soda,  22.3  per 
cent.  This  is  a  pale  yellow  to  gray  salt,  partially  soluble  in  water 
— leaving  a  white  residue  of  sulphate  of  lime — and  with  a  slightly 
saline  taste.  On  long  exposure  to  moisture  it  fails  to  pieces,  and 
hence  is  to  be  found  only  in  protected  places  or  arid  areas.  It  occurs 
associated  with  other  sulphates  and  carbonates,  as  with  thenardite 


1  Engineering  and  Mining  Journal,  LXV,  1898,  p.  310. 


348  THE  NON-METALLIC  MINERALS. 

and  mirabilite  at  Borax  Lake,  in  San  Bernardino  County,  California, 
and  with  rock  salt  at  Stassfurt  and  other  European  localities. 

6.    THENARDITE. 

Composition. — Anhydrous  sodium  sulphate.  Na2SO4,  =  sulphur 
trioxide,  43.7  per  cent;  soda,  56.3  per  cent.  Color  when  pure,  white, 
translucent  to  transparent;  hardness,  2  to  3;  specific  gravity,  2.68; 
brittle.  In  cruciform  twins  or  short  prismatic  forms  roughly  striated. 
Readily  soluble  in  water.  Is  found  in  various  arid  countries,  as  on 
the  Rio  Verde  in  Arizona,  at  Borax  Lake,  California,  and  Rhodes 
Marsh  in  Nevada,  associated  with  other  salts  of  sodium  and  boron. 

7.  EPSOMITE;  EPSOM  SALTS. 

Composition. — Sulphate  of  magnesia  MgSO4+ 7H2O,  =  sulphur 
trioxide,  32.5  per  cent;  magnesia,  16.3  per  cent;  water,  51.2  per 
cent. 

This  is  a  soft  white  or  colorless  mineral  readily  soluble  in  water 
and  with  a  bitter  saline  taste.  It  is  a  constant  ingredient  of  sea 
water  and  of  most  mineral  waters  as  well.  Being  readily  soluble  it 
is  rarely  met  with  in  nature  except  as  an  efflorescence  in  mines  and 
caves.  In  the  dry  parts  of  the  limestone  caverns  of  Kentucky,  Ten- 
nessee, and  Indiana  it  occurs  in  the  form  of  straight  acicular  needles 
in  the  dirt  of  the  floor,  and  in  peculiar  recurved  fibrous  and  columnar 
forms  or  in  loose  snow-white  masses  on  the  roofs  and  walls.  In  all 
these  cases  it  is  doubtless  a  product  of  sulphuric  acid  set  free  from 
decomposing  pyrites  combining  with  the  magnesia  of  the  limestone. 
It  is  stated  that  at  the  so-called  "alum  cave"  in  Sevier  County, 
Tennessee,  masses  of  epsomite,  very  pure  and  nearly  a  cubic  foot 
in  volume  have  been  obtained.  The  material  in  all  these  cases  is  of 
little  value,  the  chief  source  of  the  commercial  supply  being  that 
obtained  as  a  by-product  during  the  manufacture  by  evaporation 
of  common  salt  (sodium  chloride). 

In  Albany  County,  Wyoming,  are  several  lakes,  the  largest  of 
which  has  an  area  of  but  some  90  acres,  in  which  deposits  of  epsom 
salts  in  compact,  almost  snow-white  aggregates  of  small  acicular 
crystals  of  a  high  degree  of  purity  are  formed  on  a  very  large  scale. 


SULPHATES. 


349 


According  to  W.  C.  Knight,1  the  deposits  are  situated  upon  a 
high  plateau  about  three  miles  north  of  Rock  Creek,  and  lie  in  a 
huge,  undrained  depression  that  is  deepest  at  its  southern  end,  where 
it  is  about  two  miles  wide  and  lies  a  hundred  feet  or  more  below 
the  level  of  the  surrounding  country.  From  this  deepest  portion  a 
rather  broad,  shallow  valley  extends  to  the  northwest  for  several 
miles  and  contains  numerous  small  and  a  few  larger  deposits  of  sodium 
and  magnesium  salts  which  have  for  a  long  time  been  tributary  to 
the  large  epsomite  deposit  of  about  90  acres  in  extent  occupying 
the  lowest  basin.  The  deposits  are  often  covered  with  water  in 
early  spring  or  after  a  hard  storm,  but  this  soon  evaporates  and 
leaves  them  solid  epsomite  or  an  accumulation  of  mud,  sand,  and 
epsomite,  the  depth  of  which  has  been  found  by  digging  to  exceed 
ten  feet. 

Knight  regards  the  salts  as  having  been  derived  by  leaching 
from  the  decomposing  Triassic  or  Permian  red  sandstones  which 
prevail  in  the  vicinity.  Both  epsomite  and  mirabilite  occur  in  the 
rocks  and  in  the  process  are  separated  from  one  another  by  a  natural 
method  of  differential  crystallization,  the  epsomite  being  more 
soluble,  remaining  longest  in  solution  and  being  laid  down  at  a 
greater  distance  from  the  original  source. 

The  composition  of  the  deposits  is  shown  in  the  accompanying 
analyses,  No.  i  being  taken  from  near  the  head  of  the  gulch,  and 
No.  6  from  the  large  deposit  at  the  greatest  distance  from  the  source, 
the  others  from  intermediate  points : 


Constituents. 

No.  i. 

No.  2. 

No.  3. 

No.  4. 

No.  5. 

No.  6. 

Na,SO4 

Q<    46 

Qf    CA 

CTQ   QO 

47    74 

30  18 

2C    6  1 

NaCl     

yj  -ft" 

o  28 

yj-jt 

o  28 

O    ^O 

i  86 

I    OO 

r    28 

MgSO4  

4    26 

«c  20 

48  60 

<o  16 

(TO    82 

7O    1  1 

CaSCX  . 

i  80 

8.    For  description  of  POLYHALITE,  KAINITE,  and   KIESERITE, 
see  under  Halite,  p.  43. 


1  Engineering  and  Mining  Journal,  February  14,  1903. 


350  THE  NON-METALLIC  MINERALS. 

9.   ALUMS. 

Under  this  head  are  included  a  variety  of  minerals  consisting 
essentially  of  hydrous  sulphates  of  aluminum  or  iron,  with  or  with- 
out the  alkalies,  and  which  are  not  always  readily  distinguished 
from  one  another  but  by  quantitative  analyses.  The  principal  varie- 
ties are  kalinite,  tschermigite,  mendozite,  pickeringite,  apjohnite, 
halotrichite,  and  alunogen.  Alumimte  and  alunite  are  closely 
related  chemical  compounds,  but  differ  in  hardness  and  general 
physical  qualities  and  in  being  insoluble  except  in  acids. 

Although  possible  sources  of  alum,  none  of  these  minerals  have 
been  to  any  extent  utilized  in  the  United  States,  owing  to  a  lack 
of  quantity  or  inaccessibility,  the  main  source  of  the  alum  of  commerce 
being  cryolite,  bauxite,  and  clay,  as  elsewhere  noted. 

Kalinite  is  a  native  potash  alum;  composition  K2SO4.A12(SO4)3+ 
24H2O,  =  sulphur  trioxide,  33.7  per  cent;  alumina,  10.8  per  cent; 
potash,  9.9  per  cent;  water,  45.6  per  cent,  or,  otherwise  expressed, 
potassium  sulphate,  18.1  per  cent;  aluminum  sulphate,  36.3  per 
cent;  water,  45.6  per  cent.  Hardness,  2  to  2.5;  specific  gravity, 
1.75.  This  in  its  pure  state  is  a  colorless  or  white  transparent 
mineral,  crystallizing  in  the  isometric  system,  readily  soluble  in 
water,  and  characterized  by  a  strong  astringent  taste.  In  nature 
it  occurs  as  a  volcanic  sublimation  product,  or  as  a  secondary  mineral 
due  to  the  reaction  of  sulphuric  acid  set  free  by  decomposing  iron 
pyrites  upon  aluminous  shales.  Its  common  mode  of  occurrence  is, 
therefore,  in  volcanic  vents  or  as  an  efflorescence  upon  pyritiferous 
and  aluminous  rocks.  Being  so  readily  soluble,  it  is  to  be  found  in 
appreciable  amounts  in  humid  regions  only  where  protected  from 
the  rains,  as  in  caves  and  other  sheltered  places.  So  far  as  known 
to  the  author,  the  mineral  is  nowhere  found  native  in  such  quantities 
as  to  have  any  great  commercial  value. 

Tschermigite  is  an  ammonia  alum  of  the  composition 
(NH4)2SO4.A12(SO4)3+24H2O,  =  aluminum  sulphate,  37.7  per  cent; 
ammonium  sulphate,  14.6  per  cent;  water,  47.7  per  cent.  So  far  as 


SULPHATES.  351 

reported  this  salt  has  been  found  only  at  Tschermig  and  in  a 
mine  near  Dux,  Bohemia.  It  is  obtained  artificially  from  the 
waste  of  gas  works.  Mendozite  is  a  soda  alum  of  the  composition 
Na2SO4.Al2(SO4)3+  24H2O,  =  sodium  sulphate,  15.5  percent;  alumin- 
um sulphate,  37.3  per  cent ;  water,  47.2  per  cent.  The  mineral  closely 
resembles  ordinary  alum,  and  has  been  reported  from  Mendoza,  in 
the  Argentine  Republic,  hence  the  name.  Pickeringite  is  a  mag- 
nesium alum  of  the  composition  MgSO4.Al2(SO4)3+ 22H2O,  =  alu- 
minum sulphate,  39.9  per  cent;  magnesium  sulphate,  14  per  cent; 
water,  46.1  per  cent.  The  mineral  is  of  a  white,  yellowish,  or 
sometimes  faintly  reddish  color,  of  a  bitter,  astringent  taste,  and  occurs 
in  acicular  crystals  or  fibrous  masses.  Halotrichite  has  the  composi- 
tion FeSO4.Al2(SO4j3+  24H2O,  =  aluminum  sulphate,  36.9  per  cent; 
ferrous  sulphate,  16.4  per  cent;  water,  46.7  per  cent.  The  mineral 
is  of  a  white  or  yellowish  color,  and  of  a  silky,  fibrous  structure, 
hence  the  name  from  the  Greek  word  <*As?  salt,  and  QpiZ,  a  hair. 
Apjohnite  has  the  formula  MnSO4.Al2(SO4)3-f-24H2O,=  manganese 
sulphate,  16.3  per  cent;  aluminum  sulphate,  37  per  cent;  water,  46.7 
per  cent.  It  occurs  in  silky  or  asbestiform  masses  of  a  white  or  yel- 
lowish color,  and  tastes  like  ordinary  alum.  It  has  been  found  in 
considerable  quantities  in  the  so-called  "Alum  cave"  of  Sevier 
County,  Tennessee.  According  to  Safford : l 

"This  is  an  open  place  under  a  shelving  rock.  .  .  .  The  slates 
around  and  above  this  contain  much  pyrites,  in  fine  particles  and 
even  in  rough  layers.  .  .  .  The  salts  are  formed  above  and  are 
brought  down  by  trickling  streams  of  water.  .  .  .  Fine  cabinet 
specimens  could  be  obtained,  white  and  pure,  a  cubic  foot  in 
volume." 

Dana  states  that  the  cave  is  situated  at  the  headwaters  of  the 
Little  Pigeon,  a  tributary  of  the  Tennessee  River,  and  that  it  is  prop- 
erly an  overhanging  cliff  80  or  100  feet  high  and  300  feet  long,  under 
which  the  alum  has  collected.  It  occurs,  according  to  this  authority, 
in  masses,  showing  in  the  cavities  fine  transparent  needles  with  a 
silky  luster,  of  a  white  or  faint  rose  tinge,  pale  green  or  yellow. 

1  Geology  of  Tennessee,  1869,  p.  197. 


352 


THE  NON-METALLIC  MINERALS. 


Epsomite  and  melanterite  occur  with  it.  Alunogen  has  the  compo- 
sition A12(SO4)3+  i8H2O,  =  sulphur  trioxide,  36  per  cent;  alumina, 
15.3  per  cent;  water,  48.7  per  cent;  hardness,  1.5  to  2;  specific 
gravity,  1.6  to  1.8.  This  is  a  soft  white  mineral  of  a  vitreous  or 
silky  luster,  soluble  in  water,  and  with  a  taste  like  that  of  the  common 
alum  of  the  drug  stores.  It  occurs  in  nature  both  as  a  product 
of  sublimation  in  volcanic  regions,  and  as  a  decomposition  product 


^  FIG.  51.— Sketch  Map  of  Gila  River  Alum  Deposits. 

[U.  S.  Geological  Survey.] 

from  iron  pyrites  (iron  disulphide)  in  the  presence  of  aluminous 
shales.  So  far  as  the  present  writer  is  aware,  the  native  product 
has  no  commercial  value,  being  found  (on  account  of  its  ready 
solubility)  in  too  sparing  quantities  in  the  humid  East,  while  the 
known  deposits  in  the  arid  regions  are  remote  and  practically  inac- 


SULPHATES. 


353 


cessible.  A  white,  fibrous  variety  is  stated  by  Dana  to  occur  in  large 
quantities  at  Smoky  Mountain,  in  North  Carolina,  and  large  quan- 
tities of  an  impure  variety,  often  of  a  yellowish  cast,  are  found  in 
Grant  County,  en  the  Gila  River,  about  40  miles  north  of  Silver 
City,  New  Mexico.  The  mineral  is  also  found  in  Crooke  and 
Fremont  counties,  Wyoming;  in  Schemnitz,  Hungary,  and  in 
Japan. 

The  Gila  deposits  occupy  a  somewhat  circular  area — what  is  in 
fact  the  cracter  of  an  extinct  volcano.  The  country  rock  is  basalt, 
while  the  rock  which  carries  and  also  gave  rise  to  the  deposits  is 
an  andesitic  breccia,  now  highly  altered  by  solfataric  action.  The 
alum  salts — which  have  undoubtedly  originated  through  the  action 
of  acid  solfataric  waters  on  the  porous  breccia,  are  found  in  the 
form  of  incrustations  wherever  the  conditions  have  been  favorable 
to  their  formation  and  preservation.  The  original  salt  would  appear 
to  have  been  mainly  halotrichite,  but  in  many  instances  this  has 
been  dissolved  by  surface  waters,  when  the  iron  separates  out  as  an 
insoluble  oxide  and  on  evaporation  the  salt  is  deposited  in  the  iron- 
free  condition,  alunogen.  The  following  analyses  1  show  the  com- 
position of  selected  samples  of  these  salts  from  this  locality: 


HALOTRICHITE,   GILA  RIVER,   NEW  MEXICO. 


Constituents. 

A 

B 

C 

FeO 

7    04- 

I  •?    r  Q 

7  8 

ALO, 

II    77 

7    27 

1  1    OO 

SO, 

•?r     2S 

-27    jo 

•74.    d 

H,O 

4^    OQ 

6i  -*y 

4.0  02 

4.6    7 

Insoluble 

o  ^o 

IOO.O5 

99.17 

100.00 

A.  Carefully  selected  fibrous  material. 

B.  Fibrous  material  of  silky  luster. 

C.  Theoretical  composition  of  halotrichite. 


1  Bulletin  No.  315,  U.  S.  Geological  Survey,  p.  220. 


354 


THE  NON-METALLIC  MINERALS. 

ALUNOGEN,   GILA   RIVER,    NEW   MEXICO. 


Constituents. 

A 

B 

c 

A1,O, 

16  20 

Is     Z2 

SO, 

•?6    QT. 

+3  O1* 

-}A      4.2 

t-j'J 

H,O 

4.6    4.C 

4.2    ^6 

d.8    7 

Insoluble  residue  

7    62 

Total  

oo  67 

100  13 

IOO    O 

A.  Carefully  selected  crystals. 

B.  Pinkish  crusts. 

C.  Theoretical  composition  of  alunogen. 


The  upper  portion  of  the  deposit  has  naturally  been  leached  of 
all  or  a  considerable  proportion  of  its  soluble  salts  by  surface 
waters.  Though  no  borings  have  been  made  it  is  thought  that  the 
deeper-lying  portions  contain  an  almost  unlimited  supply.  It  was 
at  first  reported1  that  the  residual  rock  from  which  the  sulphates  had 
been  leached  consisted  essentially  of  bauxite,  and  it  was  so  stated 
in  the  first  edition  of  this  work  (p.  341).  Subsequent  investigation 
has,  however,  shown  this  to  be  an  error. 

In  New  South  Wales  alunogen  is  commonly  met  with  as  an  effio- 
rescence  in  caves  and  under  sheltered  ledges  of  the  Coal  Measure 
sandstone,  usually  with  epsomite,  as  at  Dabee,  County  Phillip; 
Wallerawang  and  Mudgee  road,  County  Cook;  the  mouth  of  the 
Shoalhaven  River,  and  other  places.  It  is  also  found  in  the  crevices 
of  a  blue  slate  at  Alum  Creek,  and  at  the  Gibraltar  Rock,  County 
Argyle,  and  occurs  as  a  deposit,  with  various  other  salts,  from  vol- 
canic vents  at  Mount  Wingen,  County  Brisbane,  together  with 
native  sulphur  in  small  quantities;  and  at  Appin,  Bulli,  and  Pitt 
Water,  County  Cumberland;  Cullen  Bullen,  in  the  Turon  district, 
County  Roxburgh;  Tarcutta,  County  Wynyard;  Manero;  Wingello 
Siding,  and  Capertee. 

A  specimen  in  the  form  of  fibrous  masses,  made  up  of  long,  acicular 
crystals  of  a  white,  silky  luster,  like  satin  spar,  found  as  an  efflores- 
cence in  a  sandstone  cave  near  Wallerawang,  was  found  to  have  the 
following  composition : 


1  Transactions  American  Institute  of  Mining  Engineers,  XXIV,  1894,  p.  572. 


SULPHATES. 


355 


Constituents. 

Per  Cent. 

Water 

47    ^8^ 

^Matter  insoluble  in  water 

I   070 

Alumina        

1^.108 

f      • 

34   f>2< 

Soda             

O.Q3I 

Potash 

o  3.37 

O    23s 

Total 

TOO    OOO 

Aluminite. — Aluminite  is  a  dull,  lusterless,  earthy  aluminum  sul- 
phate of  the  composition  indicated  by  the  formula  A12O3.SO8,9H2O, 
=  sulphur  trioxide,  23.3  per  cent;  alumina,  29.6  per  cent;  water, 
47.1  per  cent.  It  is  soluble  only  in  acids,  white  in  color,  opaque, 
and  occurs  mainly  in  beds  of  Tertiary  and  more  recent  clays. 

Alunite. — Composition  KvO^ALjOg^SOajbHoO,^  sulphur  triox- 
ide, 38.6  per  cent;  alumina,  37.0  per  cent;  potash,  11.4  per  cent; 
water,  13.0  per  cent.  Hardness,  3.5  to  4;  specific  gravity,  2.58  to  2.75. 
This  mineral  occurs  native  in  the  form  of  a  fibrous,  or  compact, 
finely  granular  rock  of  a  dull  luster  somewhat  resembling  certain 
varieties  of  aluminous  limestones.  It  is  infusible,  and  soluble  only 
in  sulphuric  acid.  The  more  compact  varieties  are  so  hard  and 
tough  as  to  be  used  for  millstones  in  Hungary.  No  deposits  of  such 
extent  as  to  be  of  economic  importance  are  known  within  the  limits 
of  the  United  States.  Alunite  as  an  alteration  product  of  rhyolite 
has  been  described  by  Whitman  Cross  1  as  occurring  at  the  Rosita 
Hills  in  Colorado,  the  alteration  being  brought  about  through  the 
influence  of  sulphurous  vapors  incident  to  the  volcanic  outbursts. 
The  altered  rhyolite  as  shown  by  analyses  had  the  following. compo- 
sition: Silica,  65.94  per  cent;  alumina,  12.95  Per  cent;  potash,  2.32 
percent;  soda,  1.19  per  cent;  sulphur  trioxide,  12.47  per  cent;  water, 
4.47  per  cent;  Fe2O3,  etc.,  0.55  per  cent.  This  indicates  that  the 
rock  is  made  up  of  alunite  and  quartz,  in  the  proportion  of  about 
one-third  of  the  former  to  two-thirds  of  the  latter.  Ransome  men- 
tions the  alteration  of  the  feldspar  labradorite  into  alunite  and 


1  American  Journal  of  Science,  XLI,  1891,  p.  468. 


356 


THE  NON-METALLIC  MINERALS. 


quartz  in  the  dacites  of  Goldfield,  Nevada,  the  alteration  being 
brought  about  through  the  action  of  sulphuric  acid.  The  most 
noted  occurrences  of  alunite  are  at  Tolfa,  near  Rome,  and  Montioni, 
in  Tuscany,  Italy;  Musaz,  in  Hungary;  on  the  islands  of  Milo, 
Argentiera,  and  Nevis,  in  the  Grecian  Archipelago;  Mount  Dore, 
in  France,  and  at  Bullah-Delah,  in  New  South  Wales.  The  Bullah- 
Delah  deposit  is  regarded  by  Pittman  l  as  probably  one  of  the  most 
remarkable  in  the  world.  It  occurs  in  the  form  of  a  narrow,  anti- 
clinal mountain  range,  some  three  miles  in  length  and  with  a  maxi- 
mum height  of  900  feet,  which  for  nearly  one-third  its  total  length 


<     HORIZONTAL  SCALE  ° 
VERTICAL  SCALE  0 


£?  CHAINS 


Calcareous  sandstone  with  marine  fossils 

Penno-Carboniferous 

Dip  W.40°S 

Tuffaeeous  (?)  sandstone 

yntk  carbonized  plant  remains 


FIG.  5  2. — Section  across  Bullah-Delah  Mountain,  showing  alunite  beds. 
[After  Pittman,  Mineral  Resources  of  New  South  Wales.] 

is  made  up  almost  wholly  of  alunite  of  varying  degrees  of  purity. 
The  core  of  the  range  (see  Fig.  52)  is  of  rhyolite,  and  is  flanked  on 
either  side  by  sandstone.  "  A  large,  almost  perpendicular  crown 
of  alunite,  400  feet  high,  occupies  the  center,  while  at  intervals  along 
the  backbone  of  the  ridge,  to  the  north  and  south,  are  other  pro- 
jecting crags  of  the  same  material  but  of  lesser  height.  .  .  .  Between 
the  projecting  crags  are  saddles  which  are  occupied  by  dykes  of 
dolerite  trending  across  the  range.  Naturally  a  comparatively 
small  part  of  this  enormous  mass  of  material  is  sufficiently  pure  to 
bear  mining  and  transportation.  Four  varieties  are  recognized, 
(i)  a  light  pink,  containing  1.7  per  cent  silica;  (2)  a  chalk- white 
containing  16.4  per  cent  silica;  (3)  a  purple  containing  19.5  per  cent 
silica,  and  (4)  a  granular  variety  containing  39.5  per  cent  silica. 

1  Mineral  Resources  of  New  South  Wales,  1901,  p.  415. 


SULPHATES. 


357 


At  present  only  that  carrying  less  than  10  per  cent  of  silica  is 
worked. 

Here,  as  in  the  cases  above  mentioned,  the  alunite  is  regarded 
as  an  alteration  product  of  rhyolite,  the  agents  of  alteration  being 
sulphurous  fumes  following  the  intrusion  of  dolerite. 

DeLauney  regards  the  Tolfa,  Italy,  alunite  as  a  product  of 
superficial  alteration  of  the  pyritized  portions  of  a  trachyte,  the 
products  of  decomposition  being  kaolin  or  alunite,  according  to 
the  presence  or  absence  of  a  sufficient  amount  of  pyrite  to  yield  the 
necessary  sulphuric  acid.  That  alunite  is  a  less  common  product 
of  feldspathic  decomposition  than  kalinite  is  due  to  the  special 
condition  of  pressure  and  temperature  requisite  for  the  formation 
of  the  first-named  mineral.1 

Alunite  from  the  mines  at  Tolfa  varies  considerably  in  composi- 
tion. The  crystallized  variety  contains  about  32  per  cent  alumina, 
whereas  the  cruder  specimens  which  contain  a  large  quantity  of  silica 
have  only  about  17.5  per  cent.  The  following  is  an  analysis  of  an 
average  sample:2 


Constituents. 

Per  Cent. 

Alumina 

27    60 

Sulphuric  acid 

2Q    7d 

Potash 

7    5  ^ 

Water 

1  1    2O 

Iron 

I    2O 

Silica       

22    71 

Total 

IOO    OO 

Alum  Slate  or  Shale  is  a  name  given  to  fine-grained  arena- 
ceous rocks  of  variable  composition,  but  consisting  essentially  of 
siliceous  and  feldspathic  sands  and  clays  with  disseminated  iron 
pyrites.  The  following  analyses  from  Bischof 's  Chemical  Geology 
will  serve  to  show  their  varying  nature : 


1  La  Metallogenie  de  1'Italie,  p.  127. 

2  Journal  of  the  Society  of  Chemical  Industry,  I,  1882,  p.  501. 


THE  NON-METALLIC  MINERALS. 


Constituents. 

I. 

II. 

III. 

Silica  

6C    A  A 

Alumina  

14  ST 

j5  AC 

Iron  oxides  

I.Os 

2  27 

Ijime 

T  £ 

JVtagnesia 

I      3d. 

•*? 

i  iS 

Potash 

4^O 

*  08 

Soda  

d8 

a»wo 

r  i 

Iron  pyrites.    . 

I   2\ 

2  26 

7r  •? 

Carbon  and  water.   .  . 

Undet. 

Undet 

•JO 
2  ^  O4. 

(I)  An  alum  slate  from  Opsloe,  near  Christiania,  Norway,  (II)  from  Bornholm, 
and  (III)  from  Garnsdorf,  near  Saalfeld,  Prussia. 

Concerning  No.  Ill  it  is  stated  that  on  the  roof  of  the  adit,  driven 
into  the  slate,  there  are  almost  everywhere  yellow  or  white  opaque 
stalactites,  and  more  rarely  a  green  transparent  deposit  is  produced. 
Both  consist  of  hydrated  basic  sulphate  of  alumina  and  peroxide  of 
iron.  In  the  former,  iron  predominates;  in  the  latter,  alumina. 
Both  substances  are  quite  insoluble  in  water. 

From  shales  and  slates  of  this  type  the  alum  is  obtained  by 
allowing  the  crushed  material  to  undergo  prolonged  weathering  or 
a  roasting  process.  The  essential  part  of  the  reaction  consists  in 
oxidizing  the  bisulphide  to  the  condition  of  a  sulphate  and  finally 
into  iron  sesquioxide,  with  separation  of  free  sulphuric  acid,  which 
attacks  the  alumina,  forming  an  equivalent  quantity  of  sulphate  of 
aluminum.  So  far  as  is  known  this  process  is  not  now  carried  on 
in  the  United  States. 

The  alum  shale  of  the  English  Upper  Liassic  formation  consists 
of  hard  blue  shale  with  cement  stones.  On  exposure  to  the  air  it 
gradually  becomes  incrusted  with  sulphur,  and  occasionally  with 
alum. 

In  composition  the  alum  shale  is  as  shown  in  table  on  page 

359- 

From  this  shale  potash-alum  was  formerly  made  near  Whitby 

and  Redcar,  the  aluminum  sulphate  being  extracted  from  the  shale, 
and  the  potash-salt  being  added.  The  trade,  which  since  the  days 
of  Queen  Elizabeth  has  been  largely  carried  on,  has  now  almost 
passed  away,  as  alum  is  now  manufactured  in  other  places  from  coal 
shale. 


HYDROCARBON  COMPOUNDS. 


359 


Constituents. 

Per  Cent. 

Iron  sulphide 

8  so 

Silica, 

e  I    16 

Iron  protoxide 

6  ii 

Alumina. 

18  30 

Lime  

2     Is 

^Magnesia 

O    QO 

Sulphuric  acid  

2    SO 

Potash  

Trace. 

Soda  

Trace 

Carbon  

8    20 

Water 

Total  

00   01 

XIII.    HYDROCARBON  COMPOUNDS. 

Under  the  name  hydrocarbon  compounds  are  included  a  variety 
of  substances  differing  at  times  widely  in  physical  properties  and 
in  the  proportional  amounts  of  their  main  constituents,  but  alike  in 
being  composed  essentially  of  carbon  and  hydrogen.  None  of  the 
series  crystallize  in  nature,  and  as  a  rule  the  chemical  composition 
is  so  variable  as  to  render  futile  all  attempts  at  classification  on  a 
mineralogical  basis.  In  practice  it  is  customary  to  divide  them 
into  two  main  groups,  (i)  The  Coal  Series,  (2)  The  Bitumen 
Series. 


I.   THE    COAL   SERIES. 

Here  are  included  a  variety  of  more  or  less  oxidized  hydrocarbons, 
differing  considerably  in  their  physical  properties  and  in  chemical 
composition,  but  alike  in  that  they  have  originated  through  the 
accumulation  and  -decomposition  of  plant  debris  largely  out  of 
reach  of  the  oxidizing  influence  of  the  air.  As  to  the  method  of  this 
accumulation  there  has  from  time  to  time  been  more  or  less  discussion. 


360  THE  NON-METALLIC  MINERALS. 

By  many  the  coal  beds  are  regarded  as  having  resulted  from  the 
gradual  accumulation,  in  place,  of  organic  matter  growing  on  gradu- 
ally subsiding  marshes,  or  marshes  and  swamps  subject  to  periodic 
overflow,  the  material  itself  being  largely  in  the  nature  of  sphagnous 
mosses.  By  others  it  is  thought  that  the  plant  material  was  first 
transported  by  running  streams  and  laid  down  on  the  bottoms  of 
deltas  and  lagoons;  that  the  coal  beds  are,  in  short,  as  true  sedimen- 
tary deposits  as  the  shales  and  sandstones  with  which  they  are 
associated.  This  last  view,  though  not  generally  accepted,  would 
seemingly  best  account  for  the  constant  interlamination  of  the  coaly 
and  sandy  or  clayey  material  and  the  marked  stratification  of  the 
coal  itself.  Moreover,  it  would  explain  the  almost  completely 
structureless  nature  of  many  coals,  since  calcium  sulphate,  one  of 
the  constituents  of  sea  water,  tends  to  decompose  organic  matter, 
reducing  it  to  a  pulp-like  and  at  times  almost  mucilaginous  con- 
dition. 

According  to  the  amount  of  change  that  has  taken  place  in  the 
original  plant  material,  the  amount  of  volatile  matter  still  retained 
by  it,  its  hardness  and  burning  qualities,  several  varieties  of  coal 
are  recognized,  which  are  described  somewhat  in  detail  below.  The 
general  subject,  it  may  be  said,  is  far  too  large  to  be  satisfactorily 
disposed  of  here,  and  the  reader  is  referred  to  the  special  works 
noted  in  the  bibliography. 

Peat. — This  name  is  given  to  a  material  resulting  from  the  accu- 
mulation of  plant  remains,  largely  of  the  nature  of  sphagnous  mosses, 
in  bogs,  and  which  has,  as  a  rule,  undergone  so  slight  modification 
that  the  plant  fibers  are  still  readily  recognizable,  though  where  the 
beds  have  reached  a  considerable  thickness  the  lower  portion  may 
be  reduced  to  a  dense  brownish-black  mass  somewhat  resembling 
true  coal.  These  deposits  as  existing  to-day  are  all  of  recent  origin, 
and  to  be  found  only  in  humid  and  temperate  or  north  temperate 
climates.  They  are  developed  to  an  enormous  extent  in  Ireland, 
where  they  average,  in  some  cases,  twenty-five  feet  in  thickness. 
They  are  also  abundant  on  the  continent  of  Europe  and  throughout 
the  northern  and  eastern  United  States.  In  Ireland  and  on  the 
Continent  the  material  has  been  extensively  used  as  fuel,  in  the 
first-named  country  largely  in  its  native  state,  but  in  Germany 


!.  * 

~     ~ 

^C     _i 


n 

ra    S. 


MSMmSa 

£anTanrr7TT\M  ?v- 


HYDROCARBON   COMPOUNDS.  361 

after  being  made  up  into  briquettes.1  The  material,  it  should  be 
noted,  rarely  occurs  in  such  form  as  to  be  immediately  available 
for  fuel,  the  chief  drawbacks  being  the  large  amount  of  water 
it  contains  and  its  loosely  compacted  nature.  Recourse  must  there- 
fore be  had  to  artificial  drying  and  compression.  Ordinarily  fresh 
peat,  as  taken  from  the  bog,  will  contain  from  75  per  cent  to  even 
90  per  cent  of  moisture.  By  compression,  as  in  briquette  manu- 
facture, it  is  reduced  to  about  one-fourth  its  original  bulk,  i.e.,  4 
cubic  feet  of  fresh  will  yield  i  cubic  foot  of  the  compressed  material. 
The  analyses  given  below  are  calculated  on  a  water-free  basis. 
Ordinary  air-dried  peat  will  contain  about  20  per  cent  of  moisture. 
The  analyses  are  selected  out  of  a  large  number  simply  to  show 
averages.  No.  i  is  of  material  from  Penobscot  County,  Maine;  No. 
2  from  near  Ottawa,  Canada: 


Constituents. 

I. 

II. 

Vegetable,  combustible  matter.  
Fixed  carbon                           .  . 

63.06 

T.I     21 

67-57 

2C      2  C 

Ash 

e    7? 

7  18 

Sulphur 

o  36 

O    314 

Nitrogen 

2    OQ 

I    4O 

Cheapness  of  wood  and  coal  has  caused  peat  to  be  largely  dis- 
regarded in  America,  but  recent  events  have  turned  attention  toward 
it  once  more,  and  it  seems  probable  that  within  a  few  years  numerous 
plants  will  be  established  for  converting  the  crude  material  into  a 
satisfactory  form  for  burning. 

The  rate  of  growth  of  peat,  or  otherwise  expressed,  the  rate  of 
accumulation  of  coal-bed  material,  has  been  a  matter  of  frequent 
observation.  Naturally  it  is  widely  variable  for  different  localities. 


1  A  new  method  of  making  charcoal  from  peat  has  been  patented  in  England,  and 
is  to  be  tried  in  Italy,  where  there  are  large  deposits  of  peat  which  can,  it  is  claimed, 
be  handled  very  cheaply.  In  this  process  the  peat  is  first  reduced  to  a  fine  paste 
and  leaves  the  machine  in  a  continuous  thick  tube  3  to  5  inches  in  diameter,  and 
is  then  cut  off  in  sticks  and  dried  for  three  days  on  wooden  supports  and  for  a  longer 
period  in  the  air  on  wire  netting.  After  twenty-five  days  the  sticks  become  dry  and 
hard  and  may  be  burned  as  fuel;  but  it  is  more  profitable  to  convert  these  sticks  into 
charcoal.  This  is  accomplished  in  six  hours  in  a  retort,  and  3  tons  of  peat  make 
i  ton  of  charcoal. — Engineering  and  Mining  Journal,  LXV,  February  26,  1898,  p.  248. 


362  THE  NON-METALLIC  MINERALS. 

G.  H.  Ashley  has  calculated  l  that  a  fair  average  maximum  of  peat 
growth  is  at  the  rate  of  one  foot  in  ten  years.  But  one  foot  of  the 
spongy  material  at  the  surface  will,  owing  to  pressure  and  loss 
through  decomposition,  shrink  to  a  little  over  an  inch,  and  it  is 
probable  that  one  foot  a  century  would  more  nearly  represent  the 
rate  of  accumulation  of  the  dense,  compact  material  found  in  the 
deeper  part  of  bogs.  This  material,  even  were  there  no  further 
loss  through  decomposition,  would  suffer  a  reduction  in  mass  of 
fully  two-thirds  in  passing  into  the  condition  of  ordinary  bituminous 
coal.  On  this  basis  it  would  require  300  years  for  the  accumulation 
of  material  to  form  one  foot  of  coal,  or  2,100  years  to  form  the  seven- 
foot  Pittsburg  bed,  and  probably  100,000  years,  in  round  numbers, 
for  the  total  approximate  300  feet  of  the  entire  Appalachian  coal  fields. 

Lignite  or  Brown  Coal. — This  name  is  given  to  a  brownish- 
black  variety  of  coal  characterized  by  a  brilliant  luster,  conchoidal 
fracture,  and  brown  streak.  Such  contain  from  55  to  65  per  cent  of 
carbon,  and  burn  easily,  with  a  smoky  flame,  but  are  inferior  to  the 
true  coals  for  heating  purposes.  They  are  also  objectionable  on 
account  of  the  soot  they  create,  and  their  rapid  disintegration  and 
general  deterioration  when  exposed  to  the  air.  They  occur  in  beds 
under  conditions  similar  to  the  true  coals,  but  are  of  more  recent 
origin.  The  lignitic  coals  of  the  regions  of  the  United  States  west 
of  the  Mississippi  River  are  mainly  of  Laramie  age,  and  often  show 
easily  recognizable  traces  of  their  organic  origin,  such  as  compressed 
and  flattened  stems  and  trunks  of  trees  with  traces  of  woody 
fiber. 

Jet  is  a  resinous,  coal-black  variety  of  lignite  sufficiently  dense  to 
be  carved  into  small  ornaments.  According  to  Professor  Phillips, 
it  is  simply  a  coniferous  wood,  and  still  shows  the  characteristic 
structure  under  the  microscope.  It  has  been  known  since  early 
British  times,  having  at  first  been  found  on  the  seashore  at  Whitby 
and  other  places.  The  largest  piece  on  record  was  obtained  from 
the  North  Bats,  near  Whitby.  It  weighed  some  5,180  pounds  and 
was  valued  at  about  $1,250.  The  material  is  now  regularly  mined 
both  in  the  cliffs  and  inland,  and  is  one  of  the  most  valuable  prod- 
ucts of  the  Yorkshire  coast.2 

1  Economic  Geology,  II,  1907,  p.  46. 

2  Geology  of  England  and  Wales,  p.  278. 


FIG.  i. — Typical  Moss  or  Peat  Bog  near  Augusta,  Maine. 
[After  E.  S.  Bastin,  Bulletin  No.  376,  U.  S.  Geological  Survey. 


FIG.  2. — Section  of  a  Peat  Bog,  near  Mias,  Russia. 

[From  a  photograph  by  A.  M.  Miller.] 

PLATE  XXXIII. 

[Facing  page  362.] 


HYDROCARBON  COMPOUNDS. 


363 


Bituminous  Coals. — Under  this  name  are  included  a  series  of 
compact  and  brittle  products  in  which  no  traces  of  organic  remains 
are  to  be  seen  on  casual  inspection,  but  which  under  the  microscope 
often  show  traces  of  woody  fiber,  spores  of  lycopods,  etc.  These 
coals  are  usually  of  a  brown  to  black  color,  with  a  brown  or  gray- 
brown  streak,  breaking  with  a  cubical  or  conchoidal  fracture,  and 
burning  readily  with  a  yellow,  smoky  flame.  They  contain  from  35 
to  75  per  cent  of  fixed  carbon,  1 8  to  60  per  cent  of  volatile  matter, 
from  2  to  20  per  cent  of  water,  and  only  too  frequently  show  traces 
of  sulphur,  due  to  included  iron  pyrites.  Several  varieties  of  bitu- 
minous coals  are  recognized,  the  distinctions  being  based  upon  their 
manner  of  burning.  Coking  coals  are  so  called  from  the  facility  with 
which  they  may  be  made  to  yield  coke.  Such  give  a  yellow  flame  in 
burning  and  make  a  hot  fire.  Other  varieties  of  apparently  the  same 
composition  and  general  physical  properties  can  not  be  made  to  yield 
coke,  and  are  known  as  non- coking  coals.  Cannel  coal  has  a  very 
compact  structure,  breaks  with  a  conchoidal  fracture,  has  a  dull  luster, 
ignites  easily,  and  burns  with  a  yellow  flame.  It  does  not  coke.  Its 
chief  characteristic  is  the  large  amount  of  volatile  matter  given  off 
when  heated,  whereby  it  is  rendered  of  particular  value  for  making 
gas.  Before  the  discovery  of  petroleum  it  was  used  for  the  distilla- 
tion of  oils.  Below  is  given  the  composition  of  (I)  a  coking  coal  from 
the  Connellsville  Basin  of  Pennsylvania,  and  (II)  a  cannel  coal  from 
Kanawha  County,  West  Virginia. 


Constituents. 

I. 

II. 

Water 

I  .ICX 

Volatile  matter 

29.881; 

qS.oo 

Fixed  carbon 

1:7.71;  4. 

23.^0 

Ash 

Q.8cK 

18.^0 

^ulpViur                          .... 

1.330 

Total.            

00.078 

IOO.OO 

Torbanite. — The  name  torbanite,  boghead  mineral  and  kerosene 
shale  have  been  variously  given  to  a  tough  brownish-black  to  coal- 
black,  lusterless  substance,  breaking  with  a  conchoidal  fracture 


364 


THE   NON-METALLIC  MINERALS. 


and  somewhat  resembling  cannel  coal,  which  is  found  in  both  the 
upper  and  Lower  Coal  measures  of  New  South  Wales,  Australia,  and 
near  the  base  of  the  Carboniferous  near  Bathgate,  in  Linlithgow- 
shire,  in  Scotland.  It  occurs,  according  to  E.  F.  Pittman,1  in  lentic- 
ular areas  or  patches  passing  at  the  edges  into  bituminous  or  splint 
coal  or  grading  into  carbonaceous  shale.  The  beds  are  but  a  few 
feet  in  thickness  and  the  largest  deposit  known  not  over  a  mile  in 
length.  It  is  regarded  by  different  authorities  as  due  to  the  accu- 
mulation in  lakes  of  vegetable  material,  either  sporangia  or  algae, 
and  is  therefore  classed  with  the  coals. 

The  New  South  Wales  torbanite  contains  from  70  to  80  per  cent 
of  volatile  hydrocarbons;  6  to  8  per  cent  of  fixed  carbon,  and  7  to 
20  per  cent  of  ash.  It  has  in  times  past  been  used  mainly  for  gas 
and  oil  making,  by  a  process  of  distillation.  The  best  qualities, 
yielding  from  150  to  160  gallons  of  oil  to  the  ton  or  about  20,000  feet 
of  gas  of  48  candle  intensity.2 

Anthracite  Coal. — This  is  a  deep-black,  lustrous,  hard  and 
brittle  variety,  and  represents  the  most  highly  metamorphosed 
variety  of  the  coal  series.  Traces  of  organic  nature  are  almost 
entirely  lacking  in  the  matter  of  the  anthracite  itself,  though  impres- 
sions of  ferns,  lycopods,  sigillaria,  and  other  coal-forming  plants  are 
frequently  associated  with  the  beds  in  such  a  manner  as  to  leave 
little  doubt  as  to  their  origin.  Anthracite  is  ignited  with  difficulty 
and  burns  with  little  flame,  but  makes  a  hot  fire.  Below  is  given 
the  average  composition  of  a  coal  from  the  Kohinoor  Colliery, 
Shenandoah,  Pennsylvania.3 


Constituents. 

Per  Cent. 

Water 

•}    162 

Volatile  matter 

-}    717 

Fixed  carbon 

8l    14? 

Sulphur                        

o  800 

Ash                  

II   078 

Total  

IOO.OOO 

1  Mineral  Resources  of  New  South  Wales,  p.  358. 

2  A.  Liversidge,  Minerals  of  New  South  Wales,  p.  145. 

3  F.  P.  Dewey,  Bulletin  No.  42,  United  States  National  Museum,  1891,  p.  231. 


FIG.  i. — Quarry  of  Bituminous  Sandstone,  Oklahoma. 


FIG.  2. — Quarry  of  Bituminous  Sandstone,  Santa  Cruz  District,  California. 

PLATE   XXXIV. 
[After  G.  H.  Eldridge,  U.  S.  Geological  Survey.] 

[Facing  page  364.] 


HYDROCARBON  COMPOUNDS.  365 

Until  recently  it  has  been  quite  generally  assumed  that  anthracite 
is  but  a  bituminous  coal  from  which  a  large  portion  of  the  volatile 
matter  has  been  driven  off  by  the  heat  and  pressure  incidental  to 
mountain  making  or  the  intrusion  of  igneous  rocks.  Undoubtedly 
anthracite  may  be  thus  produced  and  in  some  cases  has  been 
thus  produced,  as  in  the  Cerrillos  coal  field  of  New  Mexico, 
where  a  bituminous  coal  containing  some  30  per  cent  of  volatile 
matter  has  been  locally  converted  into  anthracite  through  the  intru- 
sion of  a  mass  of  an  andesitic  trachyte. 

Prof.  J.  J.  Stevenson  has,  however,  argued  1  that  the  difference 
between  anthracite  and  the  bituminous  coals  is  due,  not  to  metamor- 
phism  through  heat  and  pressure  after  being  buried,  but  rather  to 
the  former  having  been  longer  exposed  to  the  percolating  action  of 
water,  whereby  the  volatile  constituents  were  removed,  prior  to  its 
final  burial,  and  the  consolidation  of  the  inclosing  rocks. 

Like  the  other  coals,  anthracite  occurs  in  true  beds,  but  is  con- 
fined mostly  to  rocks  of  the  Carboniferous  Age.  Thin  seams  of 
anthracite  sometimes  occur  in  Devonian  and  Silurian  rocks,  but 
which  are  too  small  to  be  of  economic  value.  Rarely  coals 
of  more  recent  geological  horizon  have  been  formed  locally, 
altered  into  anthracite  by  the  heat  of  igneous  rocks.  Through 
a  still  further  metamorphism,  whereby  it  loses  all  its  volatile  con- 
stituents, coal  may  pass  over  into  graphite.  (See  p.  71.) 

The  principal  anthracite  coal  regions  of  the  United  States  are  in 
eastern  Pennsylvania.  From  here  westward  throughout  the  interior 
States  to  the  front  range  of  the  Rocky  Mountains  the  coals  are  all 
soft,  bituminous  coals.  Those  of  the  Rocky  Mountain  region  proper 
are  largely  lignitic,  passing  into  the  bituminous  varieties.  A  small 
field  of  anthracite  exists,  however,  in  Colorado,  and  recent  discoveries 
point  to  a  larger  one  in  Alaska.  (See  Plate  XXXII.) 

1  Bulletin  Geological  Society  of  America,  VII,  1895,  P-  525- 


366  THE  NON-METALLIC  MINERALS. 


BIBLIOGRAPHY. 

The  bibliography  of  coal,  even  though  limited  to  the  United  States,  would  be 
enormous.  In  all  cases  reference  should  be  made  to  the  publications  of  the  various 
State  surveys,  where  such  have  existed.  The  few  titles  here  given  are  of  articles  of 
general  interest,  and,  as  a  rule,  not  relating  to  the  coals  of  one  particular  locality  alone. 
WALTER  R.  JOHNSON.  A  Report  to  the  Navy  Department  of  the  United  States  on 
American  Coals  Applicable  to  Steam  Navigation  and  to  other  purposes. 

Washington,  D.C.,  1844. 

RICHARD  COWLING  TAYLOR.     Statistics  of  Coal.     The  Geographical  and  Geological 
Distribution  of  Mineral  Combustibles  or  Fossil  Fuel,  etc. 

Philadelphia,  1848. 
J.  LECONTE.     Lectures  on  Coal. 

Report  of  the  Smithsonian  Institution,  1857,  p.  119. 
T.  H.  LEAVITT.     Peat  as  a  Fuel. 

Second  Edition.     Boston,   1866,  p.  168. 
Facts  About  Peat  as  an  Article  of  Fuel. 

Third  Edition.     Boston,  1867,  p.  316. 
LEO  LESQUEREUX.     On  the  Formation  of  Lignite  Beds  of  the  Rocky  Mountain  Region. 

American  Journal  of  Science,  VII,  1874,  p.  29. 
J.  S.  NEWBERRY.     On  the  Lignites  and  Plant  Beds  of  Western  America. 

American  Journal  of  Science,  VII,  1874,  p.  399. 
JAMES  MACFARLANE.     Coal  Regions  of  America. 

New  York,  1875. 
MIALL  GREEN,  THORPE,  RUCKER,  and  MARSHALL.     Coal;   Its  History  and  Uses. 

Edited  by  Professor  Thorpe.     London,  1878,  p.  363. 
J.  S.  NEWBERRY.     On  the  Physical  Conditions  under  which  Coal  was  Formed. 

Science,  I,  March  2,  1883,  p.  89. 

CHARLES  A.  ASHBUKNER.     The  Classification  and  Composition  of  Pennsylvania  An- 
thracites. 

Transactions  of  the   American   Institute  of  Mining  Engineers,    XIV,    1885, 
p.  706 
LEO  LESQUEREUX.     On  the  Vegetable  Origin  of  Coal. 

Annual  Report  of  the  Geological  Survey  of  Pennsylvania,  1885,  p.  95. 
S.  W.  JOHNSON.     Peat  and  its  Uses  as  Fertilizer  and  Fuel. 

New  York,  1886. 
GRAHAM  MACFARLANE.     Notes  on  American  Cannel  Coal. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XVIII,  1890. 
W.  GALLOWAY.     The  South  African  Coal  Field. 

Proceedings  of  the  New  South  Wales  Institute  of  Engineers,  No.  2,  XVII,  1890, 

p.  67. 
LEVI  W.  MEYERS.     L'Origine  de  la  Houille. 

Revue  de  Quest.  Scientifique,  Brussels,  July,  1892,  pp.  5-47. 
J.  J.  STEVENSON.     Origin  of  the  Pennsylvania  Anthracite. 

Bulletin  Geological  Society  of  America,  V,  1894,  pp.  39-70. 


HYDROCARBON  COMPOUNDS.  367 

M.  L.  LEMIERE.     Sur  la  Transformation  des  Vegetaux  en  Combustibles  Folliles. 

VIII  Congres  Geologique  International,  1900,  ist  Fasciucle,  Planches  i  a  XI, 
p.  502. 
ARTHUR  L.  PARSONS.     Peat  (Its  formation,  uses  and  occurrence  in  New  York). 

New  York  State  Museum,  23d  Report  of  State  Geologist,  1903,  pp.  18-88. 
MARIUS  R.  CAMPBELL.     The  Classification  of  Coals. 

Bi-Monthly   Bulletin   American   Institue  of  Mining   Engineers,   No.   5,    1905, 
pp.  1033-1049. 

C.  W.  PARMELEE  and  W.  E.  McCouRT.     A  Report  on  the  Peat  Deposits  of  Northern 
New  Jersey. 

Annual  Report  of  the  State  Geologist,  1905,  Part  V,  p.  223. 
HENRY  B.  KUMMEL.     The  Peat  Deposits  of  New  Jersey. 

Economic  Geology,  II,  No.  i,  1907,  pp.  24-33. 
G.  H.  ASHLEY.     The  Maximum  Rate  of  Deposition  of  Coal. 

Economic  Geology,  II,  1907,  pp.  34~47- 
DAVID  WHITE.     Some  Problems  of  the  Formation  of  Coal. 

Economic  Geology,  III,  1908,  pp.  292-318. 
The  Effect  of  Oxygen  in  Coal. 

U.  S.  Geological  Survey,  Bulletin  No.  382,  1909. 
E.  NYSTROM.     Peat  and  Lignite.     (Their  Manufacture  and  Uses  in  Europe.) 

Canada  Dept.  of  Mine,  Mines  Branch,  Ottawa,  1909. 
EDSON  S.  BASTIN  and  CHARLES  A.  DAVIS.     Peat  Deposits  of  Maine. 

U.  S.  Geological  Survey,  Bulletin  No.  376,  1909. 

ERIK  NYSTROM  and  S.  A.  ANRET.     Investigation  of  the  Peat  Bogs  and  Peat  Industry 
of  Canada  during  the  Season  1908-09. 

Canada  Dept.  of  Mines,  Mines  Branch,  Bulletin  No.  i,  1909. 


2.    THE    BITUMEN   SERIES. 

Under  this  head  are  included  a  series  of  hydrocarbon  compounds 
varying  in  physical  properties  from  solid  to  gaseous  and  in  color  from 
coal-black  through  brown,  greenish,  red,  and  yellow  to  colorless. 
Unlike  the  members  of  the  series  already  described,  they  are  not  the 
residual  products  of  plant  decomposition  in  situ,  but  are  rather,  in 
part  at  least,  distillation  products  from  deeply  buried  organic  matter 
of  both  animal  and  vegetable  origin.  The  members  of  the  series 
differ  so  widely  in  their  properties  and  uses  that  each  must  be  dis- 
cussed independently.  The  grouping  of  the  various  compounds  as 
given  below  is  open  to  many  objections  from  a  strictly  scientific  stand- 


368 


THE  NON-METALLIC  MINERALS. 


point,  but,  all  things  considered,  it  seems  best  suited  for  the  present 
purposes.1 


Bituminous. 


TABULAR   CLASSIFICATION  OF  HYDROCARBONS.51 


Gaseous Marsh  gas  (Natural  gas). 

Fluidal Petroleum  (Naphtha). 

(  Pittasphalt  (Maltha). 
Viscous  and  semisolid -\  Mineral  tar. 

(  Asphalt. 

T^     . .  /  Elaterite. 

Elastlc \Wurtzillite. 

L  Albertite. 
Solid -j  Grahamite. 

(  Uintaite. 


Resinous 

Cerous  (waxy). 


f  Succinite. 
j  Copalite. 
]  Torbanite. 
[  Ambrite. 

Ozokerite. 

Hatchettite. 


TABULAR  CLASSIFICATION  OR  GROUPING  OF  NATURAL  AND  ARTIFICIAL  BITUMINOUS 

COMPOUNDS. 


» Mixed    with    limestone,   "asphal-j  Seyssel,   Val  de  Travers,   Lobsan,  Illi- 

tic  limestone."  1      nois,  and  other  localities. 

Mixed  with  silica  and  sand,  ' '  as-  j  California,  Kentucky,  Utah,  and  other 
phaltic  sand."  (      localities.     ' '  Bituminous  silica." 

"as- j  Trfnidadj  Cuba?  California,  Utah. 


Bituminous  schists 


c  i 

"e  I 


u 

I 


^   .  ,  j  Thick  oils  from  the  distillation  of  petro- 

111X11(1  ..........................  1      leum.     "Residuum." 


j  Gas-tar. 

1 


Viscous I  Pitch. 

f  Refined  Trinidad  asphaltic  earth.     Mas- 
c  ,. ,  j       tic  of  asphaltite. 

*  I  Gritted  asphaltic  mastic.      Paving  com- 

l     pounds. 


1  See  article  What  is  Bitumen,  by  S.  F.  Peckham,  Journal  of  the  Franklin  Insti- 
tute, CXL,  1895,  pp.  370  to  383. 

3  W.  P.  Blake,  Transactions  of  the  American  Institute  of  Mining  Engineers,  XVIII, 
1890,  p.  582. 


HYDROCARBON  COMPOUNDS. 


369 


Still  another  arrangement  is  that  given  below: 

TABLE    OF   OCCURRENCE    OF    IMPORTANT    NATURAL    BITUMEN.1 


Important 

natural 
bitumens. 


Pennsylvania,    California,  etc.,    in 
United     States,     Russia,    France, 


Asphaltum 

almost 

pure. 


Natural  gas Ohio, 

the 
etc. 

Natural  naphtha Found  in  petroleum  districts. 

Petroleum Pennsylvania,  Ohio,  Wyoming,  Cali- 
fornia, etc.,  in  United  States;  Russia, 
etc. 

Maltha California,  Wyoming,  Alabama,  Utah,  Col- 
orado,  Kentucky,   New   Mexico,   Ohio, 
Texas,  Indian  Territory,  etc.;    Russia, 
France,  Germany,  etc. 
North  America.. Utah,   California,  Texas, 

etc. 

Central  America. Cuba,  Mexico,  etc. 
South  America.  .Trinidad,          Venezuela, 
Peru,  Colombia,  etc. 

Europe Caucasia,     Syran-on-the- 

Volga,  Germany, 
France,  Italy,  Austria, 
etc. 

Asia Hit    on    the    Euphrates, 

Asia  Minor,  Palestine, 
etc. 

Africa Oran  in  Egypt;  probably 

other  places. 

North  America.  .West  Virginia,  Kentucky, 
Texas,  Wyoming,  Utah, 
Colorado,  California, 
Oklahoma,  Montana, 

New  Mexico. 

Central  America ..  Mexico,  Cuba,  etc. 
South  America  ...Trinidad,        Venezuela, 
Peru,    Colombia, 
etc. 

Europe Germany,      S  wit/erland, 

France,  Italy.  Sicily, 
Russia,  Austria,  Spain, 
etc. 

Asia Asia      Minor,    Palestine, 

Bagdad,  and  probably 
in  China . 

Africa Egypt,  and  probably  else- 
where in  Africa. 

Origin. — Of  the  many  views,  mainly  theoretical,  that  have  been 
put  forward  to  account  for  the  origin  of  bituminous  compounds,  but 
two  need  be  noted  in  detail  here.  Interested  readers  are  referred  to 
the  bibliography  given  on  page  398,  and  particularly  to  the  works  of 


Asphaltum. 


Asphaltic 
compounds. 


1  J.  W.  Howard,  as  quoted  by  S.  P.  Sadtler,  Journal  of  the  Franklin  Institute, 
CXL,  1895,  p.  200. 


37°  THE  NON-METALLIC  MINERALS. 

Peckham,  Orton,  and  Redwood.  F.  W.  Clarke's  excellent  sum- 
mary l  is  also  to  be  read  with  profit.  Prof.  Edward  Orton,  after 
an  exhaustive  consideration  of  the  occurrence  of  petroleum,  natural 
gas,  and  asphalt  in  Kentucky,2  gives  the  following  precise  summary : 

"i.  Petroleum  is  derived  from  organic  matter. 

"  2.  Petroleum  of  the  Pennsylvania  type  is  derived  from  the 
organic  matter  of  bituminous  shales,  and  is  probably  of  vegetable 
origin. 

"3.  Petroleum  of  the  Canadian  type  is  derived  from  limestones, 
and  is  probably  of  animal  origin. 

"4.  Petroleum  has  been  produced  at  normal  rock  temperatures 
(in  American  fields),  and  is  not  a  production  of  destructive  distilla- 
tion of  bituminous  shales. 

"5.  The  stock  of  petroleum  in  the  rocks  is  already  practically 
complete." 

Hofer3  regards  petroleum  as  of  animal  origin  only,  and  ad- 
vances the  arguments  given  below  in  support  of  his  theory: 

"i.  Oil  is  found  in  strata  containing  animal,  but  little  or  no 
plant  remains.  This  is  the  case  in  the  Carpathians,  and  in  the 
limestone  examined  in  Canada  and  the  United  States  by  Sterry 
Hunt. 

"  2.  The  shales  from  which  oil  and  paraffin  were  obtained  in  the 
Liassic  oil  shales  of  Swabia  and  of  Steirdorf,  in  Styria,  contained 
animal,  but  no  vegetable  remains.  Other  shales,  as,  for  instance, 
the  copper  shales  of  Mansfield,  where  the  bitumen  amounts  to  22 
per  cent,  are  rich  in  animal  remains  and  practically  free  from  vege- 
table remains. 

"3.  Rocks  which  are  rich  in  vegetable  remains  are  generally  not 
bituminous. 

"4.  Substances  resembling  petroleum  are  produced  by  the  decom- 
position of  animal  remains.4 

1  Data  for  Geochemistry  Bulletin  No.  330,  U.  S.  Geological  Survey,  p.  in. 

2  Report  on  the  Occurrence  of  Petroleum,  etc.,  in  Western  Kentucky.     Geological 
Survey  of  Kentucky,  John  R.  Proctor,  director,  1891. 

3  As  quoted  by  Redwood,  I,  p.  238. 

4  Dr.  Engler,  as  quoted  by  Redwood,  obtained  by  distillation  of  menhaden  oil, 
among  other  products,  a  substance  remarkably  like  petroleum,  and  a  lighting  oil 
indistinguishable  from  commercial  kerosene. 


HYDROCARBON   COMPOUNDS.  371 

"5.  Fraas  observed  exudations  of  petroleum  from  a  coral  reef 
on  the  shores  of  the  Red  Sea,  where  it  could  be  only  of  animal  origin." 

In  both  cases,  it  will  be  noted,  the  original  source  of  the  material 
was  organic  matter. 

The  second  theory,  which  advocates  an  inorganic  origin,  is  based 
largely  upon  theoretical  grounds.  It  has  been  shown  that  hydro- 
carbons may  be  formed  under  conditions  that  prevailed  deep 
in  the  earth,  below  any  possible  deposits  of  organic  matter,  and 
intimately  associated  with  igneous  intrusions.  In  brief,  hydro- 
carbons may  be  formed  from  the  reduction  of  metallic  carbides. 

The  presence  of  the  material  in  quantity  only  in  unaltered  sedi- 
mentary rocks  remote  from  all  signs  of  igneous  disturbance  must, 
however,  be  regarded  as  direct  evidence  in  favor  of  an  organic 
genesis,  whatever  may  be  said  with  reference  to  the  small  quantities 
sometimes  found  in  igneous  rocks  or  derived  from  volcanic  sources.1 

The  relationship  which  exists  between  the  solid  or  viscous  bitu- 
men and  the  fluidal  petroleum  has  not  in  all  cases  been  satisfactorily 
worked  out,  though  Peckham  has  shown  2  that  in  California  at  least 
there  are  almost  infinite  gradations  from  one  extreme  to  the  other. 
In  Ventura  County,  for  instance,  the  petroleum  is  held,  primarily, 
in  strata  of  shale,  from  which  it  issues  as  petroleum  or  maltha,  accord- 
ingly as  the  shales  have  been  brought  into  contact  with  the  atmos- 
phere, the  asphaltum  being  produced  by  a  still  further  exposure  to  the 
atmosphere  after  the  bitumen  has  reached  the  surface. 

The  relationship  between  petroleum  and  natural  gas  is  scarcely 
better  denned.  That  the  gas  can  be  derived  from  petroleum  is 
undoubted,  and  indeed  the  latter  apparently  never  occurs  free  from 
gas.  But  on  the  other  hand,  as  Professor  Orton  states,  the  gas  often 
originates  under  many  conditions  in  which  petroleum  does  not 
occur.  The  formation  of  marsh  gas  from  decomposing  plant 
remains  on  the  bottom  of  stagnant  pools,  and  its  presence  in  coal 
mines  show  with  seeming  conclusiveness  that  a  part,  at  least, 

1  Messrs.  Arnold   and   Anderson  have  recently  shown   (Bulletin  No.  322,   U.   S. 
Geological  Survey)  that  the  petroleums  of  the  Santa  Maria,  Cal.,  district,  are  derived 
from  the  Monterey  shales,  which  are  made  up  largely  of  diatom,  foraminiferal  and 
radiolarian  remains. 

2  See  report  of  the  Tenth  Census,  p.  68. 


372 


THE  NON-METALLIC  MINERALS. 


of  the  gas  is  formed  quite  independently  of  petroleum.  It  would 
seem  on  the  whole  most  probable  that  no  one  theory  was  universally 
applicable  to  all  cases. 

Marsh  Gas;  Natural  Gas.— This  is  a  colorless  and  odorless 
gas  arising  from  the  decomposition  of  organic  matter  protected  from 
the  oxidizing  influence  of  atmospheric  air.  By  itself  it  burns  quietly, 
with  a  slightly  luminous  flame,  but  when  mixed  with  air  it  forms  a 
dangerous  explosive.  It  is  this  gas  which  forms  the  dreaded  fire- 
damp of  the  miners.  In  small  quantities  this  gas  may  be  found  and 
collected,  if  desired,  from  the  bottom  of  shallow  pools  and  stagnant 
bodies  of  water  by  merely  disturbing  the  decomposing  plant  matter 
at  the  bottom,  when  the  bubbles  of  the  gas  will  rise  to  the  top.  Under 
this  head  may  properly  be  considered  the  so-called  natural  gas,  which 
has  of  late  years  become  of  so  much  importance  from  an  economic 
standpoint.  This  gas  is,  however,  by  no  means  a  simple  compound, 
but  a  variable  admixture  of  several  gases,  samples  from  different 
wells  showing  considerable  variation  in  composition,  as  well  as  those 
from  the  same  well  collected  at  different  periods.  This  last  is  shown 
by  the  seven  analyses  following,  which  may  serve  well  to  illustrate 
the  average  composition,  though  in  some  instances  the  percentage 
of  marsh  gas  has  been  found  greater.1 


Constituents. 

I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

Hydrogen    .    .    .    ...... 

i.  80 

1.64 

1.74 

2.3S 

i  86 

I  d.2 

02.84 

Q2.-2C 

CH.SC; 

02.67 

QT.  O*7 

QT.   Z8> 

Olefiant  gas  

O.2O 

o.  xs 

.0.20 

O.2<; 

O.4Q 

O  3O 

yjo° 

O  C  C 

O  11 

O  44 

O  41 

O  "71 

W.M 

Carbonic  acid.  ......... 

O.2O 

O.2< 

O.23 

O.2^ 

W»/J 

O.26 

u-55 
o  20 

Oxviien. 

O.^ 

O.^Q 

O.3^ 

O.35 

0.42 

O  3O 

Q  ze 

^.82 

•2.41 

2.Q8 

•J.C5 

3.O2 

2  80 

v'33 
34.2 

Sulphuretted  hydrogen.. 

O.I5 

O.2O 

O.2I 

0.15 

O.I5 

0.18 

"5r 

O.2O 

Total  

IOO.OO 

IOO.OO 

IOO.OO 

IOO.OO 

IOO.OO 

IOO  OO 

IOO  OO 

I,  Fostoria,  Ohio;  II,  Findlay,  Ohio;  III,  St.  Marys,  Ohio;  IV,  Muncie,  Indiana; 
V,  Anderson,  Indiana;    VI,  Kokomo,  Indiana;   VII,  Marion,  Indiana. 

Natural  gas  in  quantities  to  be  of  economic  importance  is  neces- 
sarily limited  to  rocks  of  no  particular  horizon.     It  is  not,  however, 


1  From  Orton's  Report  on  Petroleum,  Natural  Gas,  and  Asphalt  in  Kentucky,  pp. 
108-110. 


HYDROCARBON  COMPOUNDS. 


373 


indigenous  to  the  rocks  in  which  it  is  now  found,  but  occurs  in  an 
overlying  more  or  less  porous  sand  or  lime  rock  into  which  it  has  been 
forced  by  hydrostatic  pressure.  The  first  necessary  condition  for 
the  presence  of  gas  in  any  locality  may  indeed  be  said  to  depend 
upon  the  existence  of  such  a  porous  rock  as  may  serve  as  a  reservoir 
to  hold  it,  and  also  the  presence  of  an  impervious  overlying  strata  to 
prevent  its  escape.  In  Pennsylvania  the  reservoir  rock  is  a  sand- 
stone of  Carboniferous  or  Devonian  age;  in  Ohio  and  Indiana  a 
cavernous  dolomitic  limestone  of  Silurian  (Trenton)  age. 

Petroleum. — This  is  a  name  given  to  a  mixture  of  complex 
hydrocarbon  compounds,  together  with  small  amounts  of  their 
sulphur  nitrogen  and  oxygen  derivatives,  which  is  liquid  at  ordinary 
temperatures,  though  varying  greatly  in  viscosity,  of  a  black,  brown, 
greenish,  or  more  rarely  red  or  yellow  color,  and  of  extremely  dis- 
agreeable odor.  Its  specific  gravity  varies  from  0.6  to  0.9.  Through 
becoming  more  and  more  viscous,  the  material  passes  into  the  solid 
and  semisolid  forms  asphalt  and  maltha.  Chemically  it  is  considered 
as  a  mixture  of  the  various  hydrocarbons  included  in  the  marsh  gas, 
ethyline,  and  paraffin  series. 

An  ultimate  analysis  of  several  samples,  as  given  by  the  reports  of 
the  Tenth  Census  of  the  United  States  (1880),  showed  the  following 
percentages  of  the  three  essential  constituents: 


Locality. 

Hydrogen. 

Carbon. 

Nitrogen. 

West  Virginia  

1-2.  -}fQ 

85.200 

O.C,1 

Mecca,  Ohio  

13.071 

86.316 

0.23 

California  

11.819 

86.0  34 

I   IOO 

Petroleum  is  limited  to  no  particular  geological  horizon,  but  is 
found  in  rocks  of  all  ages,  from  the  lower  Silurian  to  the  most  recent, 
its  existence  in  quantities  sufficient  for  economic  purposes  being 
dependent  upon  local  conditions  for  its  generation  and  subsequent 
preservation.  Inasmuch  as  its  accumulation  in  large  quantities 
necessitates  a  rock  of  porous  nature  to  act  as  a  reservoir,  the  petro- 
leum-bearing rocks  are  mostly  sandstones,  though  not  uniformly  so. 
Petroleums  are  found  in  California  and  Texas  in  Tertiary  sands ;  in 
Colorado  in  the  Cretaceous ;  in  West  Virginia  both  above  and  below 


374  THE  NON-METALLIC  MINERALS. 

the  Crinoidal  (Carboniferous)  limestones;  in  Pennsylvania  in  the 
Mountain  sands  (Lower  Carboniferous)  and  the  Venango  sands 
(Devonian);  in  Canada  in  the  Corniferous  (Lower  Devonian)  lime- 
stones; in  Kentucky  in  the  Hudson  River  shales  (Lower  Silurian), 
and  in  Ohio  in  the  Trenton  limestone. 

In  some  instances  petroleum  oozes  naturally  from  the  ground, 
forming  at  times  a  thin  layer  on  the  surface  of  pools  of  water,  whence 
in  times  past  it  has  been  gathered  and  used  for  chemical  and  medic- 
inal purposes.  The  so-called  "Seneca  oil"  thus  used  some  fifty 
or  sixty  years  ago  was  obtained  from  a  spring  in  Cuba,  Allegany 
County,  in  New  York.  The  immense  supply  now  demanded  for  com- 
mercial purposes  is,  however,  obtained  altogether  from  artificial  wells 
of  varying  depths,  which  are  in  some  cases  self-flowing,  while  in 
others  the  oil  is  raised  by  means  of  pumps.  Wells  of  from  500 
to  1,500  feet  in  depth  are  of  common  occurrence,  while  those  upwards 
of  2,000  feet  are  not  rare.  The  principal  sources  of  petroleum  are 
in  the  United  States — New  York,  Pennsylvania,  Ohio,  and  Oklahoma, 
with  smaller  fields  in  West  Virginia,  Kentucky,  Tennessee,  Illinois, 
Indiana,  Kansas,  Louisiana,  Texas,  Colorado,  and  California.  The 
chief  foreign  source  is  the  Baku  region  on  the  Caspian  Sea,  and 
Galicia,  in  Austria. 

Uses  of  petroleum. — The  early  uses  of  petroleum  in  America 
seem  to  have  been  for  medicinal  purposes  only.  The  oil  as  pumped 
from  the  wells  has  but  a  limited  application  in  its  crude  condition 
excepting  as  a  fuel,  and  owes  its  great  value  to  the  large  and  varied 
series  of  derivatives  which  it  yields.  A  discussion  of  the  methods 
employed  in  obtaining  these  derivatives  belongs  properly  to  the 
department  of  chemical  technology,  and  can  not  be  dwelt  upon 
here.  It  must  suffice  for  present  purposes  to  say  that  the  treatment 
as  ordinarily  carried  out  at  present  involves  a  process  of  destructive 
distillation  whereby,  the  crude  material,  heated  under  pressure,  is 
resolved  into  a  variety  of  products  of  different  densities,  and  varying 
from  gaseous  through  liquid  to  solid  forms.  Prominent  among  these 
derivative  may  be  mentioned,  aside  from  the  gaseous  compounds, 
rhigolene,  gasoline,  naphtha,  benzine,  kerosene,  various  lubricating 
oils,  paraffin,  and  the  soild  residues  (coke,  etc.).  Various  phar- 
maceutical compounds  are  prepared  from  petroleum  products,  many 


HYDROCARBON  COMPOUNDS.  375 

of  which  are  well  known  to  the  public,  as  vaseline,  cosmoline,  etc. 
It  is  also  used  as  a  basis  for  ointments  and  in  soaps. 

For  full  and  detailed  information  relative  to  the  petroleum 
industry  and  general  distribution  of  allied  bituminous  compounds 
throughout  the  world,  the  reader  is  referred  to  the  works  mentioned 
in  the  bibliography,  that  of  Boverton  Redwood  being  the  most  sys- 
tematic and  complete. 

Asphaltum;  Mineral  Pitch.  -  These  are  names  given  to  what 
are  rather  indefinite  admixtures  of  various  hydrocarbons,  in  part 
oxygenated  and  which,  for  the  most  part  solid  or  at  least  highly 
viscous  at  ordinary  temperatures,  pass  by  insensible  gradations  into 
pittasphalt  or  mineral  tar,  and  these  in  turn  into  the  petroleums. 
They  are  characterized  by  a  black  or  brownish-black  color,  pitchy 
luster,  and  bituminous  odor.  The  solid  forms  melt  ordinarily  at  a 
temperature  of  from  90°  to  100°  F.,  and  burn  readily  with  a  bright 
flame,  giving  off  dense  fumes  of  a  tarry  odor.  The  fluidal  varieties 
become  solid  on  exposure  to  the  atmosphere,  owing  to  evaporation 
of  the  more  volatile  portions. 

The  nature  of  the  material,  its  mode  of  occurrence,  and  indeed 
the  uses  to  which  it  can  be  put,  vary  to  such  an  extent  with  each  indi- 
vidual occurrence  that  a  few  only  of  what  are  the  most  noted  or  best 
known  can  here  be  mentioned. 

Island  of  Trinidad. — The  occurrence  on  this  island  of  an  immense 
body  of  asphaltic  material  has  been  known  for  upwards  of  a  hundred 
years,  and  numerous,  often  widely  differing,  accounts  of  it  are  to 
be  found  in  literature.  The  latest  and  perhaps  most  satisfactory, 
when  everything  is  taken  into  consideration,  is  that  of  S.  F.  Peckham.1 
The  deposit,  which  covers  an  area  of  nearly  100  acres,  is  situated  at 
an  elevation  of  138  feet  above  the  level  of  the  sea  (see  map,  Fig.  53), 
and  on  superficial  examination  has  an  appearance  such  as  has 
caused  it  to  be  known  by  the  not  wholly  inappropriate  name  of  the 
Pitch  Lake  of  Trinidad.  The  depth  of  the  deposit,  in  various 
parts,  has  been  estimated  at  from  18  to  78  feet.  According  to 
Richardson  the  maximum  depth  is  35  feet.  Early  accounts  de- 

1  American  Journal  of  Science,  L,  1895,  pp.  33-51. 


POINT  LAB*EA 


PZTCfrLAKE 


VICINITY. 

FIG.  53. 


HYDROCARBON  COMPOUNDS.  377 

scribed  the  pitch  at  the  margin  of  the  lake  as  cold  and  hard,  becom- 
ing gradually  warmer  and  more  viscous  toward  the  center,  until  a 
point  is  reached  where  it  is  too  soft  to  support  the  weight  of  a  man 
and  actually  "boiling."  However,  this  may  have  been  years  ago; 
the  material  is  now  sufficiently  firm  over  the  entire  surface  to  sup- 
port men  and  teams.  The  deposit  is  commonly  regarded  as  a 
mud  volcano,  the  bitumen  being  still  brought  up  intermixed  with 
water  and  mud,  the  numerous  small  islands  which  occupy  the  sur- 
face of  the  lake  being  but  masses  of  earthy  matter  buoyed  up  by 
the  pitch.  Though  the  deposit  has  been  worked  for  many  years 
and  thousands  of  tons  of  asphalt  removed,  no  appreciable  impres- 
sion has  as  yet  been  produced  upon  the  amount  of  material  available. 

The  crude  material  has  the  following  composition  and  physical 
characteristics:  1 

Specific  gravity,  1.28;  hardness  at  70°  F.,  2.5  to  3  of  Dana's  scale; 
color,  chocolate-brown;  composition: 

'  Bitumen 39-83 

Earthy  matter 33-99 

Vegetable  matter 9.31 

Water 16.87 


Total 100.00 

Cuba. — Asphalt  in  some  of  its  varieties  occurs  in  nearly  every  one 
of  the  Cuban  provinces  and  in  several  instances  in  sufficient  abun- 
dance to  be  of  economic  importance.  In  all  instances  thus  far  de- 
scribed,2 the  material  occurs  in  veins  or  pockets,  or  exudes  in 
the  form  of  springs,  usually  in  serpentinous  rocks  or  limestones. 
As  long  ago  as  1837  R.  C.  Taylor  described3  a  deposit  of  asphalt 
— at  that  time  regarded  as  bituminous  coal — occurring  some  10 
miles  east  of  Havana  as  occupying  an  irregularly  branching  fis- 
sure from  i  to  9  feet  in  width  in  a  soft  clay  rock,  which  is 
now  known  to  be  a  decomposed  eruptive.  The  appearance  of  the 

1  F.  V.  Greene.     Asphalt  and  Its  Uses.     Transactions  of  the  American  Institute 
of  Mining  Engineers.,  17,  1888-89,  p.  355. 

2  See  Report  on  Geological  Reconnoissance  of  Cuba,  1901. 

3  London  and  Edinburgh  Philosophical  Magazine  and  Journal  of  Science,  X,  1837, 
p.  161. 


378 


THE  NON-METALLIC  MINERALS 


4  Feet 


vein,  in  vertical  section,  is  shown  in  Fig.  54,  the  bottom  of  the  cut 
representing  a  distance  from  the  surface  of  30  feet.  The  asphalt 
itself  was  described  as  of  a  jet-black  color,  resplendent  luster, 
conchoidal  fracture,  and  with  a  specific  gravity  varying  from 
1.42  to  1.97.  An  analysis  by 
T.  G.  Clemson  showed  63  per 
cent  volatile  matter,  34.97  per 
cent  carbon,  and  2.03  per  cent 
ash. 

Several  interesting  submarine 
deposits  exist  in  Cardinos  Bay, 
which  may  be  mentioned  on  ac- 
count of  the  unique  methods  of 
mining.  These  have  been  de- 
scribed by  J.  L.  Hance.  The 
country  rock  is  a  limestone  and 
the  asphalt  of  a  brilliant  black 
color  and  about  as  friable  as 
cannel  coal.  In  mining  a  lighter 
is  anchored  directly  over  the 
body  of  asphalt  and  a  long, 
pointed  iron  bar  raised  by  a 
winch,  on  board,  dropped  upon 
it,  the  weight  of  the  bar  being  sufficient  to  break  away  pieces  of 
the  asphalt,  which  are  then  collected  by  divers  and  sent  to  the  sur- 
face in  nets.  The  material  has  been  utilized  in  making  varnish, 
and  formerly  brought  a  high  price. 

A  large  deposit  of  an  inferior  grade,  and  used  mainly  for  roofing 
is  situated  near  Diana  Key,  15  miles  from  the  city  of  Cardenas,  and 
a  massive  bed,  some  12  feet  in  thickness,  near  Villa  Clara.  Material 
from  this  last  source  has,  during  years  past,  been  used  for  making 
the  illuminating  gas  used  in  the  city. 

Sandstones  and  limestones  are  sometimes  so  impregnated  with 
bituminous  matter  that  they  may  be  used  as  sources  of  the  material 
by  refining  processes  or  for  the  direct  manufacture  of  pavements  by 
simply  crushing.  Such  are  the  so-called  bituminous  or  asphaltic 
sand  rocks  and  limestones  of  Kentucky,  Texas,  Oklahoma, 


FIG.  54.— Asphalt  vein,  Cuba. 
[After  R.  C.  Taylor.] 


HYDROCARBON  COMPOUNDS.  379 

Utah,  Colorado,  California,  Wyoming,  and  other  States,  and  of 
Canada  and  Spain. 

According  to  G.  H.  Stone,1  the  asphaltic  sandrock  of  western 
Colorado  and  eastern  Utah  consists  of  grains  of  sand  which  are  in 
contact  with  one  another,  the  spaces  between  the  grains  being  filled 
with  asphalt,  the  proportioned  amount  of  which  varies  up  to  15  per 
cent  by  weight,  or  27  per  cent  by  volume.  One  stratum  of  fully 
charged  rock  in  the  region  described  was  nearly  40  feet  in  thickness, 
though  usually  the  strata  of  high-grade  material  are  not  more  than 
4  to  10  feet  thick  and  alternate  with  others  which  are  quite  poor 
or  barren,  so  that  the  amount  of  "  pay  rock  "  is  often  grossly 
exaggerated. 

Asphaltic  sands  and  sandrocks  are  of  common  occurrence  in  the 
immediate  vicinity  of  the  Coast  Range  in  California  from  Point 
Arena,  north  of  San  Francisco,  to  the  southernmost  part  of  the 
State.2  The  deposits  occur  almost  invariably  as  sands  and  shales, 
belonging  to  the  Neocene  formations,  impregnated  with  varying 
amounts  of  bitumen,  though  rarely  exceeding  15  to  20  per  cent  by 
weight.  The  material  is  mined  from  open  cuts,  rarely  from  shafts, 
and  is  utilized  in  large  part  for  street-paving  purposes. 

In  the  region  south  of  the  Canadian  River,  in  Oklahoma,  asphalt 
and  asphaltic  lime  and  sandstones  occur  over  extensive  areas,  the 
more  important  being  in  what  are  known  as  the  Buckhorn  and 
Brunswick  districts.  The  rocks  of  the  regions  are  wholly  sedimen- 
tary, and  the  bituminous  members  belong  mainly  to  the  Lower 
Silurian  (Ordovician) ,  Coal  Measure,  and  Cretaceous  formations. 
In  the  eastern  part  of  the  territory,  the  Ten  Mile  district,  is  found 
a  very  pure,  brittle  material  somewhat  resembling  albertite  (p.  383), 
and  for  which  the  name  impsonite  has  been  suggested.3  It  contains 
some  86  per  cent  of  carbon  and  8  per  cent  of  hydrogen.  The  material 
is  found  in  a  vein  in  greenish  gray  shales,  having  a  trend  of  15°  N. 
to  20°  E.,  and  pitching  45°  to  65°  to  the  eastward. 


1  American  Journal  of  Science,  XLII,  1891,  p.  148. 

2  See    Thirteenth    Annual  Report    State    Mineralogist  of  California,    1896,  also 
Twenty-second  Annual  Report,  U.  S.  G.  S.,  1900-1901,  Pt.  I,  pp.  209-464. 

3  After  the  Impson  Valley,  where  it  occurs.     See  Eldridge's  paper,  Twenty-second 
Annual  Report,  U.  S.  G.  S.     Richardson  regards  this  material  as  grahamite. 


38o 


THE  NON-METALLIC  MINERALS. 


At  the  Ralston  quarry  in  the  Buckhorn  district  the  rock  is  a 
massive  Ordovician  sandstone  some  15  feet  in  thickness  overlaid 
by  some  75  to  100  feet  of  conglomerate.  The  bitumen  contents 
amounts  to  between  10  and  12  per  cent.  At  the  quarry  of  the 
Gilsonite  Paving  and  Roofing  Company  in  this  same  district,  the 
bitumen  is  in  strata  referred  to  the  Lower  Coal  Measures.  (See 
section,  Fig.  55.)  The  bitumen-bearing  member  here  (No.  9  in 
section)  is  a  hard  massive  limestone,  the  upper  portion  of  which 


FIG.  55- — Section  across  quarry  of  Gilsonite  Paving  and  Roofing  Company,  showing 

bituminous  limestone  and  associated  strata. 

[U.  S.  Geological  Survey.] 

i  and  2,  conglomerate;  3,  shales;  4,  conglomerate;  5,  quartzite,  6  limestone^  bi- 
tuminous; 7,  limestone,  somewhat  bituminous;  8,  calcareous  with  wood  fiber  and 
coal;  9,  limestone  averaging  14  per  cent  bitumen;  10,  shale;  u,  conglomerate; 
12,  bituminous  shale. 

is  highly  fossiliferous,  and  the  lower  sometimes  conglomeratic.     It 
yields  on  an  average  some  14  per  cent  of  bitumen. 

Uses. — The  uses  of  the  common  type  of  material  such  as  is  known 
simply  as  asphalt  are  quite  varied.  The  wells  of  Babylon  are  stated 
to  have  been  cemented  with  it,  and  doubtless  it  was  so  used  in  other 
ancient  cities.  It  was  also,  as  at  present,  used  for  making  vessels 
water-tight.  At  the  present  day  the  refined  asphalts  are  used  as  a 
varnish  or  paint,  as  an  insulating  material,  for  waterproofing,  as  a 
cement  in  ordinary  construction,  and  as  a  cement  in  roofing  and 
paving  compounds.  For  these  purposes  it  is  first  tempered  with 
some  form  of  oil,  the  kind  and  amount  used  depending  on  the  pur- 
poses to  which  it  is  to  be  applied.  A  mixture  of  asphalt  and  sand 
forms  the  ordinary  concrete  for  sidewalks  and  basement  floors. 
The  most  extensive  use  of  asphaltic  compounds  is  at  present  for 
street  pavements,  the  material  for  this  purpose  being  mixed  with 


HYDROCARBON   COMPOUNDS.  381 

fine  sand  and  sometimes  powdered  limestone.1  The  asphaltic  sands, 
sandstones,  and  limestones  are  sometimes  so  evenly  impregnated 
with  bituminous  matter  that  they  may  be  crushed  and  applied 
directly  to  the  roadbed.  The  uses  to  which  are  put  the  higher 
grades  of  asphaltic  compounds,  such  as  are  designated  by  special 
names,  are  given  further  on. 

Manjak. — The  local  name  of  manjak  is  applied  to  a  variety 
of  bitumen  somewhat  resembling  uintaite,  occurring  on  the  island 
of  Barbados,  in  the  West  Indies.  The  material  is  a  very  pure  hydro- 
carbon of  a  black  color,  but  yielding  a  brown  powder,  high  luster,  and 
with  a  bright  conchoidal  fracture.  It  is  brittle,  and  so  friable  that  it 
can  be  ground  to  powder  between  the  thumb  and  fingers.  It  occurs 
in  seams  or  veins,  varying  from  one-fourth  of  an  inch  to  30  feet  in 
thickness,  cutting  the  country  rock,  which  is  an  argillite  or  shale, 
at  all  angles  with  the  horizon  and  with  a  general  NNE.  strike.  In 
places  the  bituminous  matter  has  saturated  the  entire  rock  in  the 
neighborhood  of  the  veins,  producing  a  shale  from  which  as  much 
as  37  gallons  a  ton  of  petroleum  have  been  obtained  by  destructive 
distillation.  Thus  far  the  greatest  development  is  along  a  vein 
200  feet  in  length,  100  feet  in  -depth,  and  from  8  to  9  feet  in  width. 
One  vein,  which  has  been  explored  to  a  depth  of  200  feet,  is  stated 
to  have  dwindled  down  to  a  width  of  6  feet,  though  30  feet  wide 
at  the  surface.2 

Manjak  is  stated  3  also  to  occur  on  the  island  of  Trinidad  some 
12  miles  from  Pitch  Lake,  with  which,  however,  it  apparently  has 
no  connection.  The  material  occurs  in  form  of  a  steeply  pitching 
seam  which  as  perforated  by  shafts  shows  a  width  of  10  feet  at  a 
depth  of  55  feet  below  the  surface  and  of  33  feet  at  a  depth  of  200 
feet.  The  material  yielded  on  analysis  as  below :  4 

1  Asphalt  and  its  Uses,  Transactions  of  the  American  Institute  of  Mining  Engineers, 
XVII,  1889,  p.  335.     See  also  The  Modern  Asphalt  Pavement,  by  Clifford  Richard- 
son, Wiley  &  Sons:  New  York,  1905. 

2  W.  Merivale,  Engineering  and  Mining  Journal,  LXVI,  1898,  p.  790;    also  the 
Mineral  Industry,  VI,  1897,  p.  54. 

3  Engineering  and  Mining  Journal,  April  14,  1906,  p.  710. 
*  Analyses  I  and  II  by  B.  Redwood,  III  by  P.  Camody. 


382 


THE  NON-METALLIC   MINERALS. 


I. 

II. 

III. 

Water  

42 

Petrolene  

17    ? 

•rf)     Qn 

Asphaltene.  .  . 

71    2 

*v-6 
66  9 

Total  bitumens  

88  7 

87    2 

CQ     Q0 

Non-bituminous  organic  matter 

50 

6  c 

Mineral  matter  

6  ^ 

u-  D 
6  o 

O.4 

Sulphur  

2    O7 

T.    06 

2     6 

Specific  gravity  

•"•y/ 
i  id. 

o-uu 

Melting-point  

360°  F 

1  •  ±5 

1  •  xo 
A6/i°  F 

4U4    r  • 

. — Like  gilsonite,  the  material  is  used  for  making  varnishes, 
insulating  electric  wires,  etc.,  bringing  the  price  of  this  mineral, 
from  $5  to  $10  a  ton,  according  to  quality  and  freedom  from  impur- 
ities. 

Elaterite;  Mineral  Caoutchouc. — This  is  the  name  given  to 
a  soft  and  elastic  variety  of  bitumen  much  resembling  pure  india- 
rubber.  It  is  easily  compressible  in  the  fingers,  to  which  it  adheres 
slightly,  of  a  brownish  color,  and  of  a  specific  gravity  varying  from 
0.905  to  i. oo.  It  has  been  described  from  mines  in  Derbyshire  and 
elsewhere  in  England,  but  so  far  as  the  writer  is  aware  is  of  no  com- 
mercial value.  Its  composition,  so  far  as  determined,  is  carbon, 
85.47  per  cent;  hydrogen,  13.28  per  cent. 

Wurtzillite.— The  name  wurtzillite  has  been  given  by  Prof.  W. 
P.  Blake  to  a  hydrocarbon  very  similar  in  appearance  to  the  uintaite 
(described  on  page  386),  but  differing  in  physical  and  chemical  prop- 
erties. It  is  a  fine  black  solid,  amorphous  in  structure,  brittle  when 
cold,  breaking  with  a  conchoidal  fracture,  but  when  warm  tough  and 
elastic,  its  elasticity  being  best  compared  with  that  of  mica.  If  bent 
too  quickly  it  snaps  like  glass.  It  cuts  like  horn,  has  a  hardness 
between  2  and  3,  a  specific  gravity  of  1.03,  gives  a  brown  streak, 
and  in  very  thin  flakes,  shows  a  garnet-red  color.  It  does  not  fuse 
or  melt  in  boiling  water,  but  becomes  softer  and  more  elastic;  in 
the  flame  of  a  candle  it  melts  and  takes  fire,  burning  with  a  bright 
luminous  flame,  giving  off  gas  and  a  strong  bituminous  odor.  It  is 
not  soluble  in  alcohol,  and  but  sparingly  so  in  ether,  in  both  of  which 
respects  it  differs  from  elaterite.  In  the  United  States  it  occurs  near 


HYDROCARBON    COMPOUNDS. 


333 


Scofield,  Carbon  County,  and  in  the  Uinta  Mountains  of  Wasatch 
County,  Utah. 

Albertite. — This  is  a  brilliant  jet-black  bitumen  compound 
breaking  with  a  lustrous,  conchoidal  fracture,  having  a  hardness  of 
between  i  and  2  of  Dana's  scale,  a  specific  gravity  of  1.097,  black 
streak,  and  showing  a  brown  color  or  very  thin  edge.  In  the  flame 
of  a  lamp  it  shows  signs  of  incipient  fusion,  intumesces  somewhat, 
and  emits  jets  of  gas,  giving  off  a  bituminous  odor;  when  rubbed  it 
becomes  electric.  According  to  Dana  it  softens  slightly  in  boiling 
water,  is  very  slightly  soluble  in  alcohol,  4  per  cent  in  ether,  and  some 
3  per  cent  soluble  in  turpentine.  The  following  is  the  composition 
as  given  by  Wetherill:  Carbon,  86.04  Per  cent ;  hydrogen,  8.96  per 
cent;  oxygen,  1.977  per  cent;  nitrogen,  2.93  per  cent;  ash,  o.io 
per  cent. 

Dr.  Antisell  made  the  following  comparative  tests  to  show  the 
relative  richness  of  the  material  in  volatile  matter: 


Constituents. 

Cannel 
Coal. 

South 
American 
Asphalt. 

Lake 
Asphalt. 

Albertite. 

Volatile  matter  

C.O.<C2 

7O.  I? 

71.67 

SQ.88 

Coke            

47.6o 

20.81; 

28.04 

-jQ.ro 

Ash              .    ...... 

I.7Q 

O.2Q 

o.e.2 

Total 

IOO.OO 

IOO.OO 

IOO.OO 

IOO.OO 

The  mineral  is  described l  as  occurring  in  "true  cutting  veins"  in 
shale  of  Lower  Carboniferous  Age  in  Hillsborough  County,  New 
Brunswick.  The  shales  themselves  contain  a  large  amount  of  car- 
bonaceous matter  and  by  distillation  have  been  made  to  yield  30 
gallons  to  the  ton  of  refined  illuminating  oil.  They  contain  immense, 
numbers  of  fossil  fish  and  are  mostly  inflammable.  The  veins  vary 
from  a  fraction  of  an  inch  to  12  feet  in  width  with  a  general  N.  65° 
east  course,  sometimes  vertical  and  sometimes  inclined  northwest- 
ward from  75°  to  80°.  They  enlarge  and  contract  very  irregularly, 
but  in  general  increase  in  thickness  as  followed  downward.  Hitch- 


1  American  Journal  of  Science,  XXXIX,  1865,  p.  267;   see  also  Dawson's  Acadian 
Geology,  3d  ed.,  pp.  231-241. 


384  THE  NON-METALLIC  MINERALS. 

cock  regarded  the  veins  as  having  been  filled  by  the  injection  of  the 
material  in  a  liquid  state  and  being  subsequently  indurated. 

Uses. — This  vein  seems  to  have  been  discovered  about  1840  by 
Dr.  Abraham  Gesner,  who,  in  1850,  took  out  a  patent  in  the  United 
States  for  the  manufacture  of  illuminating  gas  from  this  and  other 
asphalts.1  A  company  was  organized  and  for  some  years  active 
mining  operations  were  carried  on,  but  which  have  been  discontinued 
since  the  discovery  of  petroleum. 

Grahamite. — Grahamite  has  a  less  brilliant  luster  and  more 
coke-like  aspect  than  albertite.  It  has  been  described  by  Dr.  Henry 
Wurtz  as  occurring  in  shrinkage  fissures  running  N.  76°  to  80°  E. 
in  Carboniferous  shales  and  sandstones,  on  a  branch  of  Hughes 
River,  Ritchie  County,  West  Virginia.  It  is  completely  soluble  in 
chloroform  and  carbon  disulphide,  nearly  so  in  turpentine,  and  par- 
tially so  in  naphtha  and  benzine,  but  not  at  all  in  alcohol.  Melts 
somewhat  imperfectly,  beginning  to  smoke  and  soften  like  coking 
coal  at  a  temperature  of  about  400°  F.  Specific  gravity,  1.145. 

As  occurring  in  the  vein  the  material  shows  four  distinct,  though 
somewhat  irregular,  divisional  planes,  having  a  general  parallelism 
with  the  walls.  Next  to  the  walls  the  structure  of  the  mineral  is 
coarsely  granular,  with  an  irregularly  cuboidal  jointed  cleavage,  very 
lustrous  on  the  cleavage  surfaces.  The  material  in  immediate  con- 
tact with  the  walls  usually  adheres  thereto  very  tenaciously,  as  if 
fused  fast  to  the  granular  sandstone. 

The  general  aspect  of  the  mass  has  led  to  the  conclusion  that 
the  vein  is  a  fissure  which  has  been  filled  by  exudation,  in  a  pasty 
condition,  of  a  resinoid  substance  derived  from  or  formed  by  some 
organic  matter  contained  in  deep-seated  strata  intersected  by  the 
fissure  or  dike. 

J.  P.  Kimball  has  described  2  a  deposit  of  similar  material  on  the 
west  bank  of  the  Capadero  River  in  the  Huasteca,  Vera  Cruz, 
Mexico.  The  country  rock  is  a  fossiliferous  Tertiary  shale  overlaid 


1  Review  of  reports  on  the  Geological  Relations,  etc.,  of  the  coal  of  the    Albert 
Coal  Mining  Company,  situated  in  Hillsborough,  Albert  County,  New    Brunswick, 
as  written  and  compiled  by  Charles  T.  Jackson,  M.D.,  a    Fellow  of  the  Geological 
Society  of  London,  etc.,  New  York,  1852. 

2  American  Journal  of  Science,  XII,  1876,  p.  277. 


HYDROCARBON   COMPOUNDS. 


385 


by  conglomerate.  The  grahamite  occurs  in  a  fissure  some  34  inches 
in  thickness  terminating  in  an  "  overflow  "  some  6-£-  feet  in  maximum 
thickness,  thinning  away  at  the  edges,  but  the  full  extent  of  which 
was  not  determined.  The  evidence  showed  that  the  fissure  had  been 
filled  by  material  oozing  up  from  below  and  spreading  out  upon  the 
surface  prior  to  the  deposition  of  the  overlying  gravel.  The  strike 
of  the  fissure  was  nearly  north  and  south.  The  material  is  more 
uniformly  lustrous  than  that  from  Ritchie  County,  and  of  a  greater 
coherence,  though  none  the  less  distinctly  cleaved  and  jointed.  An 
analysis  of  a  sample  from  the  Cristo  mine,  as  given,  yielded  results 
as  follows: 


Constituents. 

Per  Cent. 

Volatile  matter:  Illuminating  gas  

61    32 

Sulphur  

0.46 

Water  

o  36 

Coke:  Fixed  carbon 

31    63 

Sulphur 

O    37 

Ash  

S.86 

37.86 

Specific  gravity 

100.  OO 

Carbonite  or  Natural  Coke  is  the  name  given  to  a  peculiar 
hydrocarbon  compound  occurring  in  the  form  of  beds  like  bitumin- 
ous coal,  in  Chesterfield  County,  Virginia,  and  having  a  dull  black 
and,  for  the  most  part,  lusterless  aspect,  somewhat  resembling  coke. 

An  analysis  by  Wurtz  1  yielded  the  following:  * 

Per  cent. 

Coke 84.57 

Volatile  combustible  matter J5-43 

Other  analyses  by  Dr.  T.  M.  Drown  2  on  two  portions,  the  one 
dull  and  lusterless  and  the  other  lustrous,  yielded: 


1  Transactions  of  the  American  Institute  of  Mining  Engineers,  III,  1875,  P- 

2  Idem,  XI,  1883,  p.  448. 


386 


THE  NON-METALLIC  MINERALS. 


Constituents. 

Dull 
Portion. 

Lustrous 
Portion. 

Specific  gravity  ...... 

I  37C 

I  3^O 

Loss  at  100°  C  

2.OO 

o  60 

Volatile  matter  

IE;  .47 

I  I.IO 

Ash  

3.2O 

6.68 

Fixed  carbon 

7Q  11 

81  <i 

100.00 
4.08 

100.00 

i.  60 

The  material  occurs  interbedded  with  shales  much  like  ordinary 
bituminous  coal,  there  being,  according  to  Raymond,  three  distinct 
beds  varying  from  i  foot  9  inches  to  9  feet  in  thickness,  interst ratified 
with  the  shales,  the  lowermost  bed  of  9  feet  thickness  being  under- 
laid by  fire  clay.  The  origin  of  the  material  is  in  doubt,  the  earlier 
writers  regarding  it  as  a  bituminous  coal  coked  by  the  heat  of  intru- 
sive rocks.  Later  writers  throw  doubt  upon  this  by  stating  that 
there  are  in  the  vicinity  no  intrusives  of  such  size  as  to  warrant  any 
such  assumption. 

Uses. — The  material  is  said  to  burn  without  smoke  or  soot,  like 
anthracite,  and  to  have  been  used  for  domestic  purposes. 

Uintaite;  Gilsonite.—  This  is  a  black,  brilliant,  and  lustrous 
variety  of  bitumen,  giving  a  dark-brown  streak,  breaking  with  a  beau- 
tiful conchoidal  fracture,  and  having  a  hardness  of  2  to  2.5  and  a 
specific  gravity  of  1.065  to  I<07-  ^  fuses  readily  in  the  flame  of 
a  candle,  is  plastic  but  not  sticky  while  warm,  and  unless  highly 
heated  will  not  adhere  to  cold  paper.  Its  deportment  is  stated  to  be 
much  like  that  of  sealing  wax  or  shellac.  Like  albertite  and  gra- 
hamite  it  dissolves  in  turpentine  and  is  not  soluble  in  alcohol.  It 
is  a  nonconductor  of  electricity,  but  like  albertite  becomes  electric 
by  friction.  Its  composition  as  given  is:  Carbon,  80.88  per  cent; 
hydrogen,  9.76  per  cent;  nitrogen,  3.30  per  cent;  oxygen,  6.05  per 
cent,  and  has,  o.oi  per  cent.  The  name  uintaite  was  given  this 
substance  by  W.  P..  Blake  in  1885,  after  the  Uinta  Mountains,  where 
it  was  first  found.  It  is  also  known  under  the  trade  name  of 
gilsonite,  after  S.  H.  Gilson. 


HYDROCARBON  COMPOUNDS.  387 

Occurrence. — According  to  George  H.  Eldridge1  the  gilsonite 
deposits  of  Utah  occur  filling  a  series  of  essentially  vertical  fissures 
in  Tertiary  sandstones  lying  within  the  Uncompahgre  Indian  Reser- 
vation, or  in  its  immediate  vicinity.  The  fissures  have  smooth, 
regular  walls,  and  vary  in  width  from  the  sixteenth  of  an  inch  to 
1 8  feet,  and  in  length  from  a  few  hundreds  yards  to  8  or  10  miles. 

The  larger  veins  are  somewhat  scattered,  one  lying  about  3^ 
miles  east  of  Fort  Duchesne,  a  second  in  the  region  of  the  Upper 
Evacuation  Creek,  and  the  three  others  of  most  importance  in  the 
vicinity  of  the  White  River  and  the  Colorado-Utah  line.  Besides 
these  there  is  a  1 4-inch  vein  crossing  the  western  boundary  of  the 
reservation  near  the  fortieth  parallel;  another  about  equal  size  about 
6  miles  southeast  of  the  junction  of  the  Green  and  White  rivers; 
a  third  in  the  gulch  4  or  5  miles  north  of  Ouray  Agency,  west  of  the 
Duchesne  River,  and  a  number  from  one-sixteenth  of  an  inch  to  a 
foot  in  thickness  in  an  area  about  10  miles  wide,  extending  from 
Willow  Creek  eastward  for  25  miles  along  both  sides  of  the  Green 
and  White  rivers.  The  veins  are  sometimes  slightly  faulted,  and 
often  pinch  out  to  mere  feather  edges.  The  filling  material  is  quite 
structureless  excepting  where,  as  near  the  surface,  it  has  been  ex- 
posed to  the  atmospheric  influences,  where  it  shows  a  fine  pencillate 
or  columnar  structure  at  right  angles  to  the  walls.  The  walls  of  the 
veins  are  impregnated  with  the  gilsonite  for  a  distance  of  several 
inches,  but  all  indications  point  to  the  veins  themselves  having  been 
filled,  not  by  lateral  impregnation,  but  by  injection  from  below. 

The  mining  of  uintaite  is  conducted  in  the  ordinary  manner  by 
means  of  shafts  and  tunnels.  The  work  is,  however,  attended  with 
considerable  difficulty  and  some  danger,  owing  to  the  fine  dust 
arising  from  it.  This  penetrates  the  skin  and  lungs,  and  is  a  source 
of  great  annoyance,  and  moreover  becomes  highly  explosive  when 
mixed  wTith  atmospheric  air. 

Uses. — The  principal  use  of  uintaite  thus  far  has  been  in  the 
manufacture  of  varnishes  for  ironwork  and  baking  japans.  It  is 
not  well  adapted  for  coach  varnishes.  It  has  been  also  used  for 
mixing  with  asphaltic  limestone  for  paving  material.  Other  pos- 

1  Seventeenth  Annual  Report  U.  S.  Geological  Survey,  1895-96,  Pt.  I,  p.  915. 


388 


THE  NON-METALLIC  MINERALS. 


sible  uses  suggested  are  as  below:  For  preventing  electrolytic  action 
on  iron  plates  of  ship  bottoms;  for  coating  barbed- wire  fencing,  etc.; 
for  coating  sea  walls  of  brick  or  masonry;  for  covering  paving  brick; 
for  acid  proof  lining  for  chemical  tanks ;  for  roofing  pitch;  for  insu- 
lating electric  wires;  for  smokestack  paint;  for  lubricants  for  heavy 
machinery;  for  preserving  iron  pipes  from  corrosion  and  acids;  for 
coating  poles,  posts,  and  ties;  for  torredo-proof  pile  coating;  for 
covering  wood-block  paving;  as  a  substitute  for  rubber  in  the  manu- 
facture of  cotton  garden  hose;  as  a  binder  pitch  for  culm  in  making 
brickette  and  eggette  coal. 

3.  OZOKERITE;  MINERAL  WAX;  NATIVE  PARAFFIN. 

This  is  a  wax-like  hydrocarbon,  usually  with  a  foliated  structure, 
soft  and  easily  indented  with  the  thumb  nail;  of  a  yellow-brown  or 
sometimes  greenish  color,  translucent  when  pure,  with  a  greasy  feel- 
ing, and  fusing  at  56°  to  63°  F.;  specific  gravity,  0.955.  It  is  essen- 
tially a  natural  paraffin.  The  name  is  derived  from  two  Greek 
words,  signifying  to  smell,  and  wax.  Below  is  given  the  composition 
of  (I)  samples  from  Utah,  and  (II)  from  Boryslaw,  in  Galicia. 


Constituents. 

t 

II. 

Carbon 

gir  ,17 

8s  78 

Hydrogen 

Id.  S7 

Id.  2O 

Ltr'Jl 

Total 

100  04 

TOO  O7 

The  substance  is  completely  soluble  in  boiling  ether,  carbon 
disulphides,  or  benzine,  and  partially  so  in  alcohol. 

The  following,  from  a  paper  by  Boverton  Redwood,1  will  serve  to 
show  the  character  of  the  material  from  the  various  reported  sources: 

Baku. — Specific  gravity,  0.903 ;  melting  point,  76°  C. : 


* 
Constituents. 

Per  Cent. 

8l.8o 

Gas                                

1^.80 

Coke                            

4.40 

Total                       

IOO.OO 

1  Journal  of  the  Society  of  Chemical  Industry,  XI,  1892,  p.  114. 


HYDROCARBON   COMPOUNDS.  389 

Persia. — Dark  green,  rather  hard;   specific  gravity,  0.925: 


Constituents. 

Per  Cent. 

Light  oil,  o 
Light  oil,  o 
Oil,  0.880. 
Paraffin 

740  to  o  780                        .... 

2-35 

tl° 
16.63 

53-55 
16.73 
7.24 

800  to  o  820 

Coke 

Loss 

Total 

100.  OO 

Boryslaw. — Specific  gravity,  0.930.    I,   dark  yellow;    II,   dark 
brownish  black: 


Constituents. 

I. 

II. 

Benzine,  o  710  to  o  750   

4.32 

*.<o 

Kerosene,  0.780  to  0.820  .... 

^  £ 
2S.os 

27.83 

Lubricating  oil,  0.895   ••••••• 

7.64 

6.CK 

Paraffin,  etc  

c6.fCd. 

<2.27 

Coke    

3W  j>*» 

2.8  * 

4.6^ 

Loss  ..      .... 

•5    OO 

4.82 

Total  

IOO.OO 

IOO.OO 

Occurrences. — Ozokerite  occurs  in  the  United  States  in  Emery 
and  Uinta  counties,  Utah,  where,  in  the  form  of  small  veins  in 
Tertiary  rocks,  it  extends  over  a  wide  area.  It  is  also  found  in 
Galicia,  Austria,  in  Miocene  deposits;  in  Roumania,  Hungary,  Russia, 
and  other  Asiatic  and  European  localities.  As  a  rule,  the  deposits 
are  in  beds  of  Tertiary  or  Cretaceous  age,  the  Boryslaw,  Dwiniacz, 
and  Starunia  (Galicia)  deposits  being  in  Miocene  while  the  Kouban 
deposits  are  on  the  borders  of  the  Lower  Tertiary  and  Upper 
Cretaceous.  In  Teheleken  ozokerite  is  found  accompanying  petro- 
leum in  pockets  in  beds  of  sand  above  the  clay  shales  and  Muschel- 
kalk  of  the  Aralo- Carpathian  formation.  In  southern  Utah  and 
Arizona  it  occurs  in  Tertiary  rock,  probably  Miocene. 


390  THE  NON-METALLIC  MINERALS. 

The  Galician  deposits  are  by  far  the  most  important  of  those 
above  mentioned,  -Boryslaw,  a  town  of  some  14,500  inhabitants, 
forming  the  principal  seat  of  the  mining  and  manufacturing  indus- 
try. 

The  soil  of  the  valley  in  which  Boryslaw  lies  is  a  bed  of  diluvial 
deposit  some  meters  in  thickness.  In  sinking  a  shaft,  first  yellow 
clay,  then  rounded  flints  and  gravel,  and  then  plastic  clay  are  met 
with.  Below  this  sandstone  and  blue  shale,  much  disturbed,  alter- 
nate, and  it  is  in  these  beds,  which  have  a  thickness  of  some  200 
meters,  that  the  ozokerite  is  found.  The  ozokerite-bearing  forma- 
tion lies  on  a  basis  of  petroliferous  menilite  shale,  the  strata  of  which, 
as  they  approach  the  surface,  are  disposed  almost  vertically,  but 
incline  toward  the  south.  The  strata  are  composed  of  layers  of 
coarse-grained  sandstone,  green  marl,  fine-grained  sandstone  with 
veins  of  calcite,  dark  shale  alternating  with  gray  sandy  shale,  imper- 
ceptibly merging  into  the  main  beds  of  the  non-petroliferous  sandstone 
and  shale.  Below  these  are  Carpathian  sandstones  of  the  Lower 
Eocene  (Nummulitic  sandstone)  and  Upper  Cretaceous  forma- 
tions. 

The  geological  conditions  prevailing  at  Dwiniacz  and  Starunia  are 
similar  to  those  at  Boryslaw,  but  the  ozokerite  is  more  largely  mixed 
with  petroleum.  The  soil  is  gray  and  red  diluvial  clay,  below  which 
is  a  bed  of  gravel,  lying  on  the  Miocene  formation,  in  which  the 
ozokerite  and  petroleum  occur  in  association  with  native  sulphur, 
iron  pyrites,  and  zinc  blende.  Still  lower  a  highly  porous  calcareous 
rock  is  met  with,  containing  cavities  filled  with  petroleum  and 
sulphureted  water,  and  below  this  again  is  marl  with  gypsum  and 
the  salt-clay  formation  destitute  of  petroleum.  The  ozokerite  occurs 
in  the  form  of  veins  of  a  thickness  ranging  from  a  few  millimeters  to 
some  feet,  and  is  accompanied  with  more  or  less  petroleum  and 
gaseous  hydrocarbons.  It  fills  the  many  fissures  with  which  the 
disturbed  shales  and  Miocene  sandstone  abound,  and  frequently 
forms  thus  a  kind  of  network. 

The  Boryslaw  deposit  extends  over  a  pear-shaped  area,  the  axis 
of  which  lies  E.  30°  S.  The  upper  layers  of  the  richest  portion  of 
the  deposit  occupy  an  area  of  about  21  hectares,  with  a  length  of 


HYDROCARBON  COMPOUNDS.  391 

1,000  meters  and  a  maximum  breadth  of  350  meters,  but  outside  this 
there  is  an  outer  zone  of  less  productive  territory  which  increases  the 
total  superficies  to  about  60  hectares,  with  dimensions  of  1,500  meters 
by  560  meters.  The  deposit  narrows  considerably  as  the  depth 
increases,  and  at  a  distance  of  100  meters  from  the  surface  of  the 
ground  has  a  breadth  of  only  200  meters. 

Uses. — The  crude  ozokerite,  after  being  freed  so  far  as  possible 
from  impurities,  is  melted  and  cast  into  loaves  or  blocks  of  the  form 
of  a  truncated  cone,  and  weighing  about  50  to  60  kilos.  There  are 
two  or  three  recognized  commercial  qualities  of  the  melted  and 
cast  ozokerite.  The  first  quality  is  transparent  in  thin  sheets,  and 
it  color  ranges  from  yellow  to  greenish  brown.  Adulteration  by  means 
of  crude  petroleum,  heavy  oils,  the  residues  from  refineries,  asphal- 
tum,  and  even  earthy  matter,  are  not  unknown,  and  occasionally 
by  a  process  of  double  casting  the  exterior  of  the  block  is  made  to  differ 
in  quality  from  the  interior. 

The  refined  material  is  known  as  ceresin.  It  is  used  for  candles, 
as  an  adulterant  or  a  complete  substitute  for  beeswax,  and  in  the 
manufacture  of  ointments  and  pomades.  A  residual  product  from 
the  purifying  process,  of  a  hard,  waxy  nature,  is  combined  with  india- 
rubber  and  used  as  an  insulating  material  for  electrical  cables. 
In  this  form  it  is  known  as  okanite.  A  ball  blacking,  used  on  the 
heels  of  shoes,  is  also  manufactured  from  it. 

The  names  Scheererite,  Hatchettite,  Fichtelite,  and  Konlite  are 
applied  to  simple  hydrocarbons  allied  to  ozokerite  found  in  beds 
of  peat  and  coal,  but,  so  far  as  the  writer  is  aware,  never  in  such 
abundance  as  to  be  of  commercial  value. 


4.  RESINS. 

Succinite;  Amber. — The  mineral  commonly  known  as  amber 
is  a  fossil  resin  consisting  of  some  78.94  parts  of  carbon,  10.53  parts 
of  oxygen,  and  10.53  parts  of  hydrogen,  together  with  usually  from 
two  to  four-tenths  of  a  per  cent  of  sulphur.  It  is  not  a  simple  resin, 
but  a  compound  of  four  or  more  hydrocarbons.  According  to 


392  THE  NON-METALLIC  MINERALS. 

Berzelius,  as  quoted  by  Dana,  it  consists  mainly  (85  to  90  per 
cent)  of  a  resin  which  resists  all  solvents,  along  with  two  other  resins 
soluble  in  alcohol  and  ether,  an  oil,  and  2j  to  6  per  cent  of  succinic 
acid. 

The  mineral  as  found  is  of  a  yellow,  brownish,  or  reddish  color, 
frequently  clouded,  translucent  or  even  transparent,  tasteless, becomes 
negatively  electrified  by  friction,  has  a  hardness  of  2  to  2.5,  a  specific 
gravity  when  free  from  inclosures  of  1.096,  a  conchoidal  fracture, 
and  melts  at  250°  to  500°  F.  without  previous  swelling  but  boils 
quietly,  giving  off  dense  white  fumes  with  an  aromatic  odor  and 
very  irritating  effect  on  the  respiratory  organs. 

As  above  noted,  amber  is  a  fossil  resin  or  pitch,  an  exudation 
product  principally  of  the  Pinus  succinijert  a  now  extinct  variety 
of  pine  of  the  Tertiary  period. 

Occurrence. — Amber  or  closely  related  compounds  has  been 
found  in  varying  amounts  at  numerous  widely  separated  localities, 
but  always  under  conditions  closely  resembling  one  another.  The 
better- known  localities  are  the  Prussian  coast  of  the  Baltic;  on  the 
coast  of  Norfolk,  Essex,  and  Suffolk,  England ;  the  coasts  of  Sweden, 
Denmark,  and  the  Russian  Baltic  provinces ;  in  Galicia,  Westphalia, 
Poland,  Moravia,  Norway,  Switzerland,  France,  Upper  Burmah, 
Sicily,  Mexico,  the  United  States  at  Martha's  Vineyard,  and  near 
Trenton  and  Camden,  New  Jersey. 

The  substance  occurs  in  irregular  masses,  usually  of  small  size. 
One  of  the  largest  masses  on  record  weighed  18  pounds.  This  is 
now  in  the  Berlin  Museum.  A  mass  found  in  the  marl  pits  near 
Harrisonburg,  New  Jersey,  weighed  64  ounces.  This  last  is  pre- 
sumably not  true  amber,  since  it  contained  no  succinic  acid,  which 
is  now  regarded  as  the  essential  constituent. 

The  amber  of  commerce  comes  now,  as  for  the  past  two  thousand 
years,  mainly  from  the  Baltic,  where  it  occurs  in  a  strata  of  lignite- 
bearing  sands  of  Lower  Oligocene  age.  According  to  Berendt,1 
there  are  two  amber-bearing  strata,  the  one  carrying  t'le  amber  in 
nests  and  both  underlaid  and  overlaid  by  clayey  seams,  and  the 

1  Schriften  der  Physikalisch-okonomischen  Gesellschaft,  VII,  1866. 


HYDROCARBON  COMPOUNDS.  393 

second  and  lower  a  glauconitic  sand  commonly  known  as  the  blue 
earth.  The  material  is  mined  by  open  cuts  where  the  strata  come 
to  the  surface,  by  means  of  shafts  and  tunnels,  as  in  coal  mining, 
and  by  dredging  or  diving,  in  the  latter  case  the  material  having 
been  derived  originally  from  the  amber-bearing  strata  and  redeposited 
on  the  present  sea-bottom.1 

The  pieces  obtained  vary  from  the  size  of  a  pea  to  that  of  the  hand. 
The  annual  product  at  present  amounts  to  some  300,000  pounds, 
valued  at  about  $1,000,000.  The  price  of  the  material  varies  greatly 
with  the  size  and  purity  of  the  pieces.  Pieces  of  one-fourth  pound 
weight  bring  about  $15  a  pound,  while  the  small  granules  will  not 
bring  one-twentieth  that  amount.  The  value  of  the  material  is 
often  lessened  by  the  presence  of  flaws  and  impurities  or  inclosures, 
such  as  insects  and  twigs  of  plants. 

Uses. — Amber  is  used  mainly  in  jewelry,  in  small  ornamentations, 
and  smokers'  goods,  the  smaller  pieces  being  used  in  making  varnish. 
The  clear  pieces  and  chippings  have  of  late  been  compressed  by  a 
newly  discovered  process  into  tablets  some  6  by  3  by  i  inches  in 
size,  which  can  be  utilized  in  the  manufacture  of  articles  for  smokers' 
use. 

Retinite. — The  name  retinite  is  used  by  Dana  to  include  a  con- 
siderable series  of  fossil  resins  allied  to  amber,  differing  mainly  in 
containing  no  succinic  acid.  They  occur  in  beds  of  brown  coal  of 
Tertiary  and  Cretaceous  Age,  much  as  does  the  amber  proper.  The 
principal  varieties  that  have  thus  far  proven  of  any  economic  impor- 
tance are  noted  below: 

Chemawinite. — This  is  the  name  given  by  Professor  Harring- 
ton,2 to  an  amber- like  resin  found  associated  with  woody  debris 
on  the  southeast  shore  of  Cedar  Lake  in  Canada.  The  material 
occurs  in  granular  form  and  in  small  sizes  only,  such  as  are  quite 
unsuited  for  manufacturing  purposes.  The  true  gum-bearing 
stratum,  if  such  exists,  has  not  yet  been  discovered,  the  material 
thus  far  found  being  washed  up  by  waves  on  t  ie  beach.  Accord  - 


1  According  to  the  Engineering  and  Mining  Journal  of  May  20,  1893,  tne  dredg- 
ing process  on  the  Baltic  coast  has  been  discontinued  as  no  longer  profitable. 

2  American  Journal  of  Science,  XLII,  1891,  p.  332. 


394  THE  NON-METALLIC  MINERALS. 

ing  to  O.  J.  Klotz,1  the  beach  matter  resembles  the  refuse  of  a 
sawmill,  no  stones  and  very  little  sand  being  associated  with  the 
debris,  which  is  everywhere  underlaid  by  clay.  The  principal 
beach  was  estimated  to  contain  some  700  tons  of  granular  material. 

A  somewhat  similar  resin  is  found  in  the  lignite  and  soft  greenish 
sandstone  near  Kuji,  Japan.2  It  is  reported  as  being  of  inferior 
quality,  opaque,  cloudy,  and  much  fissured.  It  is,  however,  mined 
and  shipped  to  Tokio,  where  it  is  presumably  worked  up  into  small 
ornaments. 

The  so-called  Burmese  amber,  or  Burmite  from  the  Hukong 
Valley,  is  reported  as  occurring  in  a  soft  blue  clay,  probably  of  Lower 
Miocene  Age,  and  in  lumps  not  exceeding  the  size  of  a  man's 
hand. 

Gum  copal. — The  name  copal  or  gum  copal  h  made  to  cover, 
commercially,  a  somewhat  variable  series  of  resins  found  for  the  most 
part  buried  in  the  sands  in  tropical  and  subtropical  regions.  They 
are  in  general  amber-like  or  resin-like  in  appearance,  of  a  hardness 
inferior  to  that  of  true  amber,  of  a  light  yellow  to  brown  color,  brill- 
iant glass-like  luster,  transparent  to  translucent,  and  have  a  con- 
choidal  fracture.  When  cold  they  are  brittle  and  can  be  readily 
crushed  to  powder,  but  possess  a  slight  amount  of  elasticity.  When 
rubbed  on  cloth  they  become  electric  and  emit  a  peculiar  resinous 
odor.  The  specific  gravity  varies  from  i  to  i.io.  When  heated 
the  material  softens,  swells  up,  and  bubbles,  finally  melting,  remain- 
ing liquid  until  carbonized.  It  burns  with  a  yellow  smoky  flame; 
is  partially  soluble  in  alcohol,  wholly  so  in  ether,  and  also  in  turpen- 
tine on  prolonged  digestion.  The  so-called  Kauri  gum  is  a  light 
amber-colored  variety  from  the  Dammara  Australis,  a  living  conifer- 
ous tree  of  New  Zealand.  The  principal  source  is  the  northern 
portion  of  the  Auckland  provincial  district  which  has  exported  since 
1863  (and  up  to  1897)  some  134,630  tons  of  gum  valued  at 
^5,394,687,  the  product  for  1890  being  7,438  tons  valued  at 

£378,563. 

The  gum-digging  industry  is  one  that  gives  employment  to  both 

1  American  Jeweler,  No.  2,  XII,  1892. 

*  Transactions  of  the  American  Institute  of  Mining  Engineers,  V,  1876,  p.  265. 


HYDROCARBON  COMPOUNDS.  395 

Europeans  and  natives.1  The  gum  is  found  but  a  short  distance 
below  the  surface,  and  is  dug  with  the  aid  of  a  few  implements,  the 
entire  outfit  often  consisting  of  a  steel  prod,  a  spade,  and  knife  and 
haversack.  With  the  copal  is  often  found  the  more  amber-like  resin 
ambrite,  which  has  a  slightly  greater  hardness,  a  specific  gravity 
of  1.034,  a  yellowish  gray  to  reddish  color  and  which  yields  on  an- 
alysis carbon,  76.88;  hydrogen,  10.54  per  cent,  and  oxygen,  12.77 
per  cent.  It  becomes  strongly  electric  by  friction  and  is  insoluble  in 
alcohol,  ether,  chloroform,  benzine,  or  turpentine,  and  burns  with 
yellow,  smoking  flame.  Quite  similar  to  the  kauri  gum  is  the  copal 
of  the  African  coasts.  According  to  Dr.  F.  Welwitsch2  gum  of  the 
west  coast  and  probably  all  the  gum  resin  exported  under  this  name 
from  tropical  Africa  is  to  be  regarded  as  a  fossil  resin  produced  by 
trees  which,  in  periods  long  since  past,  adorned  the  forests  of  that 
continent,  but  which  are  at  present  either  totally  extinct  or  exist 
only  in  a  dwarfed  posterity.  The  gum,  which  is  called  by  the  Bunda 
negroes  Ocate  Cocoto,  or  Mucocoto,  is  found  in  the  hilly  or  mountain- 
ous districts  all  along  the  coast  of  Angola,  including  the  districts  of 
Congo  and  Benguella,  and  is  brought  by  the  natives  to  the  different 
market  places  on  the  coast  of  Angola,  including  the  districts  of  Congo 
and  Benguella.  The  larger  quantities  of  the  resin  are  mostly  found 
in  the  sandy  soil,  and  it  is  apparently  limited  in  its  geographical  dis- 
tribution with  that  of  the  tree  Adansonia  digitata,  the  lands  in  the 
Government  of  Benguella  extending  along  the  mountain  terrace  of 
Amboin,  Selles,  and  Mucobale,  south  of  the  Cuanza  River  being 
most  productive,  having  yielded  between  1850  and  1860  some 
1,600,000  pounds  of  gum  a  year. 

"It  is  a  general  and  widely  spread  opinion,"  writes  Welwitsch, 
"  that  the  gum  copal  in  Angola  is  gathered  from  trees;  but  this,  accord- 
ing to  my  own  observation,  is  obviously  erroneous,  for  the  gum 
copal  is  either  dug  out  of  the  loose  strata  of  sand,  marl,  or  clay,  or 
else  it  is  found  in  isolated  pieces  washed  out  and  brought  to  the 
surface  of  the  soil  by  heavy  rainfalls,  earthfalls,  or  gales;  and  such 

1  Report  of  the  Mining  Industry   of  New  Zealand  for  1888.     In  the  report  for  1887 
it  is  stated  that  "according  to  the  last  census"  the  number  of  persons  employed  in 
the  occupation  of  gum  digging  was  1,283. 

2  Journal  of  the  Linnaean  Society  of  London,  Botany,  IX,   1866,  p.  287. 


39$  THE  NON-METALLIC  MINERALS. 

pieces,  where  found,  induce  the  negroes  to  dig  for  larger  quantities 
in  the  adjacent  spots.  This  digging  after  larger  quantities  is,  as 
may  be  supposed,  often  very  successful;  but  sometimes  it  is  less 
satisfactory,  or  totally  without  result,  just  in  the  same  manner  as  with 
people  digging  for  gold.  At  times  numerous  larger  and  smaller 
pieces  of  copal  are  found  close  to  the  surface  of  the  sand,  or  within 
the  depth  of  a  few  feet;  while  in  other  places,  after  digging  to  the 
depth  of  5  to  8  or  even  10  or  more  feet,  only  single  pieces,  or  some- 
times none  at  all,  are  brought  to  light. 

"  The  secured  resin  is  cleaned  by  washing  and  packed  in  sacks, 
to  be  ready  for  sale  in  the  markets  on  the  coast.  Different  varieties 
of  unequal  value  being  often  obtained  on  the  same  spot,  the  resin, 
when  brought  to  market,  has  to  be  sorted  before  being  sold.  It  is 
classified  mostly  according  to  its  color,  and  the  price  is  determined 
by  weight.  The  deep-colored  quality  is  generally  worth  double 
the  price  of  the  lighter  sort.  The  shape  in  which  the  gum  is  found 
is  quite  variable;  it  often  has  the  form  of  an  egg,  a  ball,  or  a  drop, 
at  other  times  it  looks  like  a  flat,  pressed  cake,  and  it  is  also  met 
with  in  sharp-canted  pieces.  The  pieces  vary  as  much  in  size  as  in 
shape;  they  are  rarely  larger  than  a  hen's  egg,  and  there  are  many 
much  smaller,  others  (which,  however,  seldom  occur)  are  as  big  as 
a  man's  fist,  or  even  a  child's  head,  weighing  three  to  four  pounds 
and  more.  All  the  pieces  of  different  shape  and  size  have  one  com- 
mon characteristic,  namely,  that  on  their  surface  they  are  covered 
with  a  thinner  or  thicker  close-sticking,  whitish,  nearly  chalky  crust, 
which  exhibits  on  many  pieces  veins  or  network,  while  in  most 
instances  it  covers  the  surface  like  an  earthy,  powdery  coat.  The 
surface  of  fresh-broken  pieces  appears  conchoid  al,  with  finely  radiat- 
ing lines  in  each  conchoidal  impression.  The  luster  is  glossy,  the 
mass  is  hard  and  transparent  to  a  certain  depth,  and  where  scratched 
with  a  knife  or  needle  it  leaves  a  white  powdered  stroke.  It  can 
easily  be  scraped  with  a  knife  into  powder  which,  if  sprinkled  over 
red-hot  coals,  changes  instantaneously  into  thick  vapors,  at  first 
with  a  slight  yellow  color,  with  a  strong  aromatic  smell,  somewhat 
similar  to  that  of  incense.  Large  pieces  brought  into  contact  with  a 
light  soon  burn  up,  developing  at  the  same  time  the  above-mentioned 
vapors.  When  chewed  it  crackles  between  the  teeth  without  leaving 
a  noticeable  taste." 


HYDROCARBON  COMPOUNDS.  397 

"  The  interior  of  the  Angola  copal  pieces,  when  not  mixed  with 
earthy  substances,  or  with  remains  of  bark,  is  even  glossy  and  trans- 
parent; but  I  have  never  observed  insects  in  any  of  the  numerous 
samples  which,  partly  in  Angola  and  partly  at  Lisbon,  came  under 
my  notice,  while  in  the  copal  sent  to  Lisbon  from  the  province  of 
Mozambique,  on  the  east  coast  of  Tropical  Africa,  various  hymenop- 
terous  insects  are  to  be  met  with.  The  different  colors  of  the  copal 
of  Angola  just  described  are  connected  more  or  less  with  its  avail- 
ability for  varnishes,  etc.  Thus  the  copal  dealers  distinguish  three 
sorts,  namely,  (i)  red  copal  gum  (gomma  copal  vermellia) ;  (2)  yellow 
(G.C.  amarella);  (3)  whitish  (G.C.  bianca).  The  red  and  whitish 
sorts  furnish  the  best  and  finest  varnish,  and  therefore  are  most  in 
request  and  the  dearest,  while  the  whitish  quality  is  sold  at  the 
lowest  price." 

According  to  Burton  2  the  present  limit  of  distribution  of  the 
gum-yielding  trees  on  the  east  coast  is  less  extensive  than  that  of  the 
extinct  forests  which  have  yielded  the  true  or  "ripe"  copal,  or  "san- 
darusi,"  as  it  is  locally  called.  Every  part  of  the  coast  from  Ras 
Gomani,  in  south  latitude  3,  to  Ras  Delgado,  in  10°  41',  with  a  mean 
depth  of  30  miles  inland,  may  be  called  the  copal  coast.  The 
material  is  found  in  red,  sandy  soil,  but  is  not  evenly  distributed, 
occurring  rather  in  patches,  as  though  produced  by  isolated  trees. 
Dr.  Kirk  considers  this  gum  as  a  product  of  trees  of  the  same  species 
as  those  at  present  producing  the  raw  gum  called  by  the  natives  and 
Arabs  sandarusiza  miti  or  chakazi;  that  is,  the  Trachylobium  mozam- 
bicense  Peters.  The  gum  when  dug  from  the  soil  has  superficially 
a  peculiar  pebbled  appearance,  best  described  as  "  goose  skin,"  and 
which  Burton  considered  as  due  to  the  impress  of  the  sandy  grains 
in  which  it  had  been  buried,  but  which  Dr.  Kirk  regards  as  due  to 
the  structure  of  the  cellular  tissues  of  the  tree.  The  copal  when 
freshly  dug  has,  according  to  this  authority,  exteriorly  no  trace  of  the 
goose-skin  structure. 

As  is  the  case  with  the  New  Zealand  and  West  African  gums,  the 
methods  of  digging  are  very  crude,  careless,  and  desultory.  The 

1  Journal  <x  the  Linnaean  Society  of  London,  Botany,  IX,  1866,  pp.  291-293. 

2  Lake  Region  of  Central  Africa,  II,  p.  403.     See  also  report  by  Dr.  M.  C.  Cooke, 
on  the  gums,  resins,  etc.,  in  the   India   Museum,   or  produced   in   India.      London, 
India  Museum,  1874. 


398  THE  NON-METALLIC  MINERALS. 

diggings  are  mostly  beyond  the  jurisdiction  of  Zanzibar,  but  as  this 
is  the  principal  port,  most  of  the  material  is  known  commercially  as 
Zanzibar  copal. 

BIBLIOGRAPHY. 

M.  C.  COOK.     Report  on  Gums,  Resins,  Oleo-Resins,  and  Resinous  Products  in  the 
India  Museum,   or  produced  in  India. 

London,  India  Museum,   1874,  pp.  98-103. 

S.  F.  PECKHAM.     Report  on  the  Production,  Technology,  and  Uses  of  Petroleum  and 
its  Products. 

Report  of  the  Tenth  Census  of  the  United  States,  X,  1880. 
This  important  report  contains  a  very  complete  bibliography  on  the  subject 
up  to  date  of  publication. 
G.  W.  GRIFFIN.     The  Kauri  Gum  of  New  Zealand. 

U.  S.  Consular  Reports,  II,  1881,  p.  241. 
R.  W.  RAYMOND.     The  Natural  Coke  of  Chesterfield  County,  Virginia. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XI,  1882,  p.  446. 
EDWARD  ORTON.     A  Source  of  the  Bituminous  Matter  in  the  Devonian  and  Sub- 
Carboniferous  Black  Shales  of  Ohio. 

American  Journal  of  Science,  XXIV,  1882,  p.  171. 

ORAZIO  SILVESTI.     On  the  Occurrence  of  Crystallized  Paraffin  in  the  Hollow  Spaces 
of  a  Basaltic  Lava  from  Paterno,  near  Mount  Etna. 

Journal  of  the  Society  of  Chemical  Industry,  I,   1882,  p.  180. 
WILLIAM  MORRISON.     The  Mineral  Albertite  and  the  Strathpeffer  Shales. 

Transactions  of  the  Edinburgh  Geological  Society,  V,  1883-1888,  p.  34. 

A  New  Mineral  Tar  in  Old  Red  Sandstone :  Ross-shire. 

Transactions  of  the  Edinburgh  Geological  Society,  V,   1883-1888,  p.  500. 
S.  F.  PECKHAM.     The  Origin  of  Bitumens. 

American  Journal  of  Science,  XXVIII,  1884,  p.  105. 

EDWARD  ORTON.     The  Trenton  Limestone  as  a  Source  of  Petroleum  and  Natural 
Gas  in  Ohio  and  Indiana. 

Eighth  Annual  Report  U.  S.  Geological  Survey,  Pt.  2,  1886-87,  PP-  483-662. 
J.  L.  KLEINSCHMIDT.     Asphalt  Deposits  in  the  Formation  of  Coal. 

Berg-  und  Huttenminnische  Zeitung,   XL VI,    1887,  p.   78. 

JOSEPH  M.  LOCKE.      Gilsonite  or  Uintaite.      A  New  Variety  of  Asphaltum  from 
the  Uintah  Mountains,  Utah. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XVI,  1887,  p. 
162. 

A.  RATEAU.     Note  sur  1'Ozokerite,  ses  Gisements,  son  Exploitation  a  Boryslaw  et  son 
Traitement  Industriel. 

—  Annales  des  Mines,  XI,  Pt.  i,  1887,  p*  147.     See  also  Engineering  and  Mining 
Journal,  XLV,  1888,  p.  415. 

Verarbeitung  des  galizischen  Erdwachses. 

Berg- und  Hiittenmannische  Zeitung,  XL VII,  1888,  p.  435. 
A.  LIVERSIDGE.     Torbanite. — Cannel  Coal  or  Kerosene  Shale. 

Minerals  of  New  South  Wales,  1888,  p.  145. 
MAX  VON  ISSER.     Die  Bitumenschatze  von  Seefeld. 

Berg-  und  Huttenmannisches  Jahrbuch,  XXXVI,   1888,  Pt.  i,  p.  I. 


HYDROCARBON  COMPOUNDS.  399 

L.  BABU.     Note  sur  L'Ozokerite  de  Boryslaw  et  les  Petroles  de  Sloboda  (Galicie). 

Annales  de  Mines,  XIV,   1888,  p.   162.     See  also  Transactions  of  the  North 
of  England   Institute  of  Mining  and    Mechanical   Engineers,   XXXVIII,    1889, 

I-  15- 
F.  V.  GREENE.     Asphalt  and  its  uses. 

Transactions  of  the  American  Institute  of  Mining  Engineers,   XVII,    1888, 

P-  355- 
WILLIAM  MORRISON.     Elaterite:    A  Mineral  Tar  in  Old  Red  Sandstone,  Ross-shire 

Mineralogical  Magazine,  VIII,  May,  1888,  October,  1889,  p.  133. 
HENRY  WURTZ.     The  Utah  Mineral  Waxes. 

Engineering  and  Mining  Journal,  XLVIII,  July  13,  1889,  p.  25. 

• Uintaite  a  variety  of  Grahamite. 

Engineering  and  Mining  Journal,  XLVIII,  August  10    1889,  p.  114. 
WILLIAM  P.  BLAKE.     Wurtzilite  from  the  Uintah  Mountains,  Utah. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XVIII,   1890, 
p.  497. 

• Uintaite,  Albertite,  Grahamite,  and  Asphaltum  described  and  compared,  with 

Observations  on  Bitumen  and  its  Compounds. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XVIII,    1890, 

P-  563- 
HENRY  WURTZ.     Wurtzilite,  Prof.  Blake's  New  Mineral. 

Engineering  and  Mining  Journal,  XLIX,   1890,  p.  59. 
Bituminous  Rock,  California. 

Tenth  Annual  Report  of  the  California  State  Mineralogist,  1890. 
E.  W.  HILGARD.     Report  on  the  Asphaltum  Mine  of  the  Ventura  Asphalt  Company 

Tenth  Annual  Report  of  the  California  State  Mineralogist,   1890,  p.  763. 
Asphalt  and  Petroleum  in  Mexico. 

Journal  of  the  Society  of  Chemical  Industry,  IX,   1890,  p.  426. 
GEORGE  VALENTINE.     On  a  Carbonaceous  Mineral  or  Oil  Shale  from  Brazil:  Its 
Formation  and  Composition.     As  a  Key  to  the  Origin  of  Petroleum. 

Proceedings  of  the  South  Wales  Institute  of  Engineers,  XVII,  August  8,  1890, 
p.  20. 
S.  DEUTSCH.     Ozokerite  in  Galicia. 

Journal  of  the  Iron  and  Steel  Institute,  1891,  p.  311. 
HENRY   WURTZ.     A   Review   of   the   Chemical    Literature   of   the   Mineral   Waxes. 

Engineering  and  Mining  Journal,  LI,  March  28,  1891,  p.  326. 
CLARENCE  LOWN;  H.  BOOTH.     Fossil  Resins. 

New  York,  1891. 

EDWARD  ORTON.     Report  on  the  Occurrence  of  Petroleum,  Natural  Gas,  and  Asphalt 
Rock  in  Western  Kentucky. 

Geological  Suivey  of  Kentucky,  J.  R.  Proctor,  Director,  1891. 
BOVERTON  REDWOOD.     The  Galician  Petroleum  and  Ozokerite  Industries. 

The  Journal  of  the  Society  of  Chemical  Industry,  XI,  1892,  p.  93. 
E.  T.  DUMBLE.     Note  on  the  Occurrence  of  Grahamite  in  Texas. 

Transactions  of  the  American  Institute  of  Mining  Engineers,  XXI,  1892,  p.  601. 
HENRY  M.  CADELL.  Pertoleum  and  Natural  Gas;  their  Geological  History  and 
Production. 

Transactions  of  the  Edinburgh  Geological  Society,  VII,  Pt.  i,  p.  51,  1893-94. 


400  THE  NON-METALLIC  MINERALS. 

J.  G.  GOODCHILD.     Some  of  the  Modes  of  Origin  of  Oil  Shales,  with  Remarks  upon 
the  Geological  History  of  some  other  Hydrocarbon  Compounds. 

Transactions  of  the  Edinburgh  Geological  Society,  VII,  1895-96,  p.  121. 
C.  EG.  BERTRAND;   B.  RENAULT.     The  Kerosene  Shale  of  New  South  Wales. 

Transactions  of  the  North  of  England  Institute  of  Mining  and  Mechanical 
Engineers,  XLIV,  1895,  p.  76. 
S.  F.  PECKHAM.     On  the  Pitch  Lake  of  Trinidad. 

American  Journal  of  Science,  L,  1895,  p.  33.     See  also  the  Geological  Magazine, 
II,  1895,  P'-  4i6. 

What  is  Bitumen  ? 

Journal  of  the  Franklin  Institute,  CXL,  1895,  p.  370. 

BOVERTON  REDWOOD;   GEORGE  L.  HOLLO  WAY.     Petroleum  and  Its  Products. 
2  Vols.,  London,  1896. 

Asphaltum  and  Bituminous  Rock. 

Thirteenth  Report  of  the  California  State  Mineralogist,  1896,  p.  35. 
OTTO  LANG.     Trinidad  Asphalt. 

Transactions  of  the  North  of  England  Institute  of  Mining  and  Mechanical 
Engineers,  XLV,  Pt.  3,  March,  1896,  p.  i. 
GEORGE  H.  ELDRIDGE.     The  Uintaite  (Gilsonite)  Deposits  of  Utah. 

Seventeenth  Annual  Report,  U.  S.  Geol.  Survey,  1895-96,   Pt.  I. 
WALTER  MERIVALE.     Barbadoes  Manjak. 

Engineering  and  Mining  Journal,  LXVI,  1898,  p.  790. 
JOHN  RUTHERFORD.     Notes  on  the  Albertite  of  New  Brunswick. 

Journal  of  the  Federated  Canadian  Mining  Institute,  III,  1898,  p.  40. 
I.  C.  WHITE.     Origin  of  Grahamite. 

Bulletin  of  the  Geological  Society  of  America,  X,  1899,  pp.  277-284. 
GEORGE  H.  ELDRIDGE.     The  Asphalt  and  Bituminous  Rock  Deposits  of  the  United 
States. 

Twenty-second  Annual  Report,  U.  S.  G.  S.,  1900-1901,  Pt.  I,  pp.  209-464. 
SEIFFERT.     Die  Erdwachs  und  Petroleum  Industrie  Boryslaws,  Zeit.  fur  das  Berg- 

Hiitten  und  Salinen-wesen  im  Preussischen  Staate,  Vol.  XLIX,  1901,  pp.  87-96. 
P.  DAHMS.     Ueber  das  Vorkommen  und  die  Verwendung  des  Bernsteins,  Zeit.  fur 
pratische  Geologic,  Vol.  IX,   1901,  pp.  201-211. 


XIV.  MISCELLANEOUS. 

i.  GRINDSTONES;  WHETSTONES;  AND  HONES. 

The  custom  of  sharpening  edge  tools  on  pieces  of  stone  has  been 
practiced  by  barbarous  and  civilized  nations  ever  since  the  adoption 
of  cutting  implements  of  any  kind,  however  crude  and  of  whatever 
materials. 

With  the  first  crude  implements,  it  is  safe  to  say  almost  any  stone 
possessing  the  requisite  grit  would  serve  to  produce  the  rough  edge 
.desired.  With  the  improvement  in  the  cutting  implement  there  has, 


MISCELLANEOUS  401 

however,  been  necessitated  a  corresponding  improvement  in  the 
character  of  the  sharpening  implement  as  well.  Formerly,  it  may 
be  safely  assumed,  every  man  used  that  which  was  most  accessible 
and  could  be  made  to  best  answer  its  purpose.  Now  the  grindstone 
and  whetstone  industry  is  as  well  organized  as  any  other  branch  of 
manufacture,  and  forms  no  inconsiderable  feature  of  the  nation's 
trade.  Localities  are  ransacked  and  material  is  brought  from  far 
and  near,  carried  long  distances,  overland  or  across  the  ocean,  to 
the  workshops  of  the  manufacturer  to  be  cut  into  the  desired  shapes 
and  sizes,  classified  and  assorted  according  to  quality,  and  sent  abroad 
once  more  to  meet  the  demands  of  the  ever-increasing  trade.  The 
use  of  the  grindstone,  it  should  be  noted,  is  not  confined  merely  to 
sharpening  edge  tools,  but,  as  will  be  noted  later,  they  are  made  from 
a  variety  of  materials,  and  of  an  equal  variety  of  sizes,  from  the 
2-inch  wheel  of  novaculite,  used  by  jewelers,  to  a  coarse  grit  monster 
of  over  2  tons  weight  for  the  grinding  of  rough  castings  in  machine 
shops,  or  wood  pulp  in  paper  manufacture. 

A  stone  to  be  suitable  for  grinding  purposes  must  possess  a  fine 
and  even  grain,  free  from  all  hard  spots  and  inequalities  of  any  kind. 
It  is  essential,  too,  that  the  various  particles  of  which  it  is  composed 
be  cemented  together  with  just  sufficient  tenacity  to  impart  the 
necessary  strength  to  the  stone,  and  yet  allow  them  to  crumble  away 
when  exposed  to  friction,  thus  continually  presenting  fresh  sharp 
grains  and  surfaces  to  act  upon  the  material  being  ground.  Simple 
as  these  essential  qualities  may  seem  they  are  in  reality  but  rarely 
met  with  in  perfection,  and  the  majority  of  grindstones  now  on  the 
market  are  quarried  from  a  comparatively  limited  number  of  sources. 
If  the  stone  be  too  friable  it  wears  away  too  rapidly,  and  the  grind- 
ing done  is  coarse  and  uneven;  a  sharp  edge  or  polish  is  unobtainable 
If  too  hard  it  glazes  and  loses  its  cutting  qualities,  or  cuts  so  slowly 
as  to  be  no  longer  desirable.  If,  moreover,  the  particles  composing 
the  stone  adhere  with  too  little  tenacity,  the  stone,  particularly  if  it 
be  a  large  one,  such  as  is  used  for  grinding  castings,  is  liable  to  burst, 
perhaps  to  the  serious  injury  of  workmen  and  machinery. 

The  requisite  qualities  as  above  enumerated  are  found  mainly  in 
those  stones  that  have  originated  as  sandy  deposits  on  sea  bottoms 
and  have  undergone  little  if  any  metamorphism — in  other  words,  in 


402  THE  NON-METALLIC  MINERALS. 

sandstones.  For  some  particular  reason,  or  rather  owing  to  certain 
peculiar  conditions,  although  sandstones  were  formed  throughout  a 
great  number  of  periods  in  the  earth's  history,  those  formed  during 
the  Carboniferous  age  seem  best  adapted  for  the  purpose,  and  from 
stone  found  somewhere  in  this  formation  are  manufactured  a  large 
share  of  the  grindstones  now  in  use. 

A  majority  of  the  grindstones  now  found  in  the  markets  of  the 
United  States  are  made  from  sandstones  quarried  from  the  Upper, 
Middle,  and  Lower  Carboniferous  formations  of  Ohio,  Michigan, 
Nova  Scotia,  New  Brunswick,  England  or  Scotland.  A  few  are,  o~ 
have  been,  made  from  stone  from  Missouri  and  Kentucky.  The 
Ohio  stones  are  obtained  nearly  altogether  from  quarries  in  the  sub- 
Carboniferous  sandstones  at  or  near  Berea,  Amherst,  Bedford,  Con- 
stitution, Massillon,  Marietta,  Independence,  and  Euclid.  Few  if 
any  of  the  quarries  are  worked  wholly  for  grindstones,  but  in  the 
majority  of  cases  the  stone  is  sought  for  building  purposes  as  well, 
and  the  grindstone  output  may  be  merely  incidental,  certain  layers 
only  being  adapted  for  the  latter  purpose.  This  is  well  illustrated 
by  the  following  section,  as  shown  at  one  of  the  Amherst  quarries 
and  as  described  1  by  Professor  Orton,  the  State  geologist.  The 
reader  will  understand  that  by  section  is  meant  the  various  layers 
exposed  in  the  quarry  wall,  or  that  would  be  passed  through  in  dig- 
ging or  boring  from  the  surface  downward. 

At  Amherst,  then,  the  stone  lies  as  follows,  beginning  at  the  sur- 
face: 

Feet. 

Drift  material  (soil,  sand,  etc.) i  to    3 

Worthless  shell  rock 6  to  10 

Soft  rock  used  only  for  grindstones 12 

Building  stone 3 

Bridge  stone .  •. 2 

Grindstone. 2 

Building  and  grindstone 10 

Building  stone 4  to    7 

Building  stone  or  grindstone 12 

1  Geological  Survey  of  Ohio,  V,  p.  586. 


MISCELLANEOUS  403 

Commenting  on  the  condition  of  affairs  as  here  displayed,  Pro- 
fessor Orton  says: 

"As  will  be  noticed  in  this  section,  the  different  strata  are  not 
applicable  alike  to  the  same  purpose,  and  the  uses  for  which  the 
different  grades  of  material  can  be  employed  depend  principally 
upon  the  texture  and  the  hardness  of  the  stone.  The  softest  and 
most  uniform  in  texture  is  especially  applicable  for  certain  kinds  of 
grinding,  and  is  used  for  grindstones  only,  and  the  production  of 
these  forms  an  important  part  of  the  quarry  industry.  In  its  differ- 
ent varieties  the  material  is  applicable  to  all  kinds  of  grinding,  and 
stones  made  from  it  are  not  only  sold  throughout  this  country,  but 
are  exported  to  nearly  all  parts  of  the  civilized  world.  Some  of  the 
finest-grained  material  is  also  used  in  the  manufacture  of  whetstones. 
There  are  various  points  in  the  system  of  the  Berea  grit  where  the 
stone  is  adapted  to  this  use,  but  such  a  manufacture  is  best  carried 
on  when  joined  with  a  large  interest  in  quarrying,  so  that  the  small 
amount  of  suitable  material  can  be  selected;  and  thus  it  happens  that 
only  at  Amherst  and  at  Berea  are  whetstones  manufactured  in  large 
quantities." 

Below  are  given  in  brief  outline  the  sources  and  main  character- 
istics of  the  principal  grindstones  now  in  the  market,  beginning  with 
those  of  the  United  States.  In  speaking  of  the  texture  of  any  stone, 
that  of  Berea  has  been  taken  as  the  standard.  This  is  the  stone  most 
used  for  grinding  cutting  tools,  such  as  axes  and  scythes.  It  must 
be  remarked  here  that  the  term  Berea  grit  is  applied  not  merely  to 
the  stone  from  the  immediate  vicinity  of  the  town  of  Berea,  but  is 
rather  a  general  name  applied  to  this  particular  subdivision  of  the 
sub- Carboniferous  formation  of  Ohio  and  extending  over  a  wide 
field. 

Berea. — Medium  fine;  blue  gray,  light  yellowish,  or  nearly  white. 
For  edge  tools  in  general;  the  finer  varieties  also  used  for  whetstones. 

Amherst. — Medium  fine,  like  the  Berea,  being  a  part  of  the  same 
formation.  Light  gray,  with  small  rust-colored  spots  due  to  iron 
oxides.  For  grindstones  and  whetstones  for  edge  tools  in  general; 
the  softer  varieties  for  saws. 

Independence. — Similar  to  the  Amherst,  and  especially  adapted  for 
the  manufacture  of  large  grindstones  for  dry  grinding;  stones  said 
not  to  glaze  when  used  for  this  purpose. 


404  THE  N  ON- MET  A  LUC  MINERALS. 

Bedford. — Rather  coarser,  though  of  even  texture  and  filled  with 
brown  spots  of  iron  oxide.  Especially  adapted  for  grinding  springs. 

Euclid. — Fine,  light  bluish  gray;   for  wet  grinding  edge  tools. 

Massillon. — Medium  to  rather  coarse;  the  microscope  shows  it 
to  be  an  aggregate  of  rounded,  colorless  grains  of  quartz,  with  little, 
if  any,  cementing  material.  Not  so  finely  compacted  as  the  last,  and 
small  fragments  can  be  readily  broken  from  the  sharp  edges  by  means 
of  the  thumb  and  fingers.  Color,  light  yellowish  or  pinkish;  for  edge 
tools,  springs,  files,  and  nail-cutters'  face  stones,  but  mainly  for  the 
dry  grinding  of  castings. 

Constitution. — Medium;  light  gray  and  rather  more  friable  than 
the  last.  A  variety  of  textures,  however,  and  all  kinds  of  grits  for 
wet  grinding  are  furnished. 

Huron,  Michigan. — Fine;  uniform  blue-gray  color,  with  numer- 
ous flecks  of  silvery  mica.  Smells  strongly  of  clay  when  breathed 
upon.  For  wet  grinding  of  edge  tools ;  produces  a  fine  edge. 

The  Joggins,  Nova  Scotia. — Fine  gray;  of  uniform  texture;  used 
for  wet  grinding  all  kinds  of  edge  tools ;  the  large  stones  for  grinding 
springs,  sad  irons,  and  hinges;  extensively  exported  to  the  United 
States. 

Bay  oj  Chaleur,  New  Brunswick. — Fine  dark  bluish  gray;  of 
firm  texture;  smells  strongly  of  clay  when  breathed  upon.  Resem- 
bles the  stone  of  Huron,  Michigan,  but  contains  less  mica.  Used  in 
the  manufacture  of  table  cutlery;  also  machinists'  tools  and  edge  tools 
in  general. 

Newcastle,  England. — Light  gray  and  yellowish;  with  a  sharp 
grit;  rather  friable,  and  texture  somewhat  coarser  than  that  of  the 
Berea  stone,  which  it  otherwise  somewhat  resembles.  The  finer 
grades  used  for  grinding  saws  and  the  coarser  and  harder  ones  for 
sad  irons,  springs,  pulleys,  shafting,  for  bead  and  face  stones  in  nail 
work,  and  for  dry  grinding  of  castings ;  also  used  by  glass  cutters. 

Wicker  sly,  England. — A  dull,  brownish  or  yellowish,  somewhat 
micaceous  stone  of  medium  texture  and  rather  soft.  For  grinding 
saws,  squares,  bevels,  and  cutlers'  work  in  general. 

Liverpool,  or  Melting,  England. — Dull  reddish;  a  somewhat 
loosely  compacted  aggregate  of  siliceous  sand,  so  friable  that  the  sharp 
angles  are  easily  crumbled  away  by  the  thumb  and  fingers.  A  very 
sharp  grit,  used  for  saws  and  edge  tools,  particularly  axes  in  ship-yards. 


•  . 


FIG.  2. 

PLATE   XXXV. 

Microstructure  of  Mica  Schist  used  in  making  Hones.    Fig.  i,  Cut  across  the  Grain. 

Fig.  2,  Cut  parallel  with  Grain.     The  enlargement  is  the  same  in  both  cases. 

[U.  S.  National  Museum.] 

[Facing  page  404.] 


MISCELLANEOUS.  405 

Craigleith,  Scotland. — Fine-grained  and  nearly  white.  A  very 
pure  siliceous  sandstone  with  a  sharp  grit.  Said  to  be  the  best  stone 
known  for  glass  cutting,  though  the  Newcastle,  Warrington,  and 
Yorkshire  grits  are  also  used  for  a  similar  purpose. 

For  whetstones  the  same  qualities  are  essential  as  for  grindstones, 
though  as  a  rule  the  whetstones  are  designed  for  a  finer  class  of 
work,  and  hence  a  finer  grade  of  material  is  utilized.  For  sharpening 
scythes  and  other  coarse  cutting  tools,  however,  the  same  stone  is 
used  as  for  grindstones,  the  same  quarry  producing  stone  for  build- 
ing, grindstones,  and  whetstones,  as  above  noted.  The  so-called 
Hindostan,  or  Orange  stone,  from  Orange  County,  Indiana,  is  a  very 
fine-grained  siliceous  sandstone  of  remarkably  sharp  and  uniform 
grit,  and  which  for  carvers  and  kitchen  implements  is  unexcelled. 
The  so-called  Labrador  stone  is  also  a  sandstone  of  a  dark  blue-gray 
color  and  of  less  sharp  grit  than  that  just  mentioned.  Many  scythe- 
stones  like  "Indian  Pond"  "  Chocolate,"  "Farmers'  Choice," 
"Black  Diamond,"  "Vermont  Quinebaug,"  and  the  "Lamoille," 
are  fine-grained  mica  schists  from  New  Hampshire  and  Vermont 
quarries.  These  as  a  rule  are  very  fine-grained  schistose  dark-gray 
rocks,  sometimes  of  a  light  chocolate  color  on  a  freshly  fractured 
surface.  The  microscope  shows  them  to  consist  of  a  compact  and 
slightly  schistose  aggregate  of  quartz  and  mica  in  which  are  fre- 
quently included  very  abundant  small  octahedral  crystals  of  mag- 
netic iron  and  sometimes  garnets.  (See  Plate  XXXV.)  So  abundant 
are  these  magnetic  granules  in  some  of  these  rocks,  especially  those 
of  Grafton  County,  New  Hampshire,  as  to  constitute  an  important 
feature,  and  it  is  doubtless  in  part  to  them  that  the  stone  owes  its 
excellent  abrasive  qualities.  Magnetite,  it  will  be  remembered,  has 
a  hardness  of  about  6.5  of  the  scale,  and  constitutes  a  very  consider- 
able proportion  of  the  ordinary  emery  of  commerce.  We  have  here, 
then,  what  is  almost  a  natural  equivalent  of  the  artificial  emery  stone, 
the  compact  groundmass  of  quartz  and  mica  serving  as  a  binding 
material  for  the  magnetite  grains  while  they  perform  their  work  in 
wearing  away  the  implement  being  ground.  A  part  of  the  abrading 
quality  of  these  stones  is,  however,  due  to  the  abundant  quartz  and 
mica  scales  and  their  peculiar  arrangement  in  relation  to  one 
another. 

The  well-known  Water  of  Ayr,  Scotch  hone,  or  snake  stone,  as 


406 


THE  NON-METALLIC  MINERALS. 


it  is  variously  called,  is  also  a  very  compact  schist.     It  is  said  to 
come  from  Dalmour,  in  Ayrshire,  Scotland. 

The  name  novaculite  is  applied  to  a  very  fine-grained  and  com- 
pact rock  consisting  almost  wholly  of  chalcedonic  silica,  and  which, 
owing  to  the  fineness  of  its  grit,  is  used  only  in  the  finer  kinds  of  work, 
as  in  sharpening  razors,  knives,  and  the  tools  of  engravers,  car- 
penters, and  other  artisans.  The  true  novaculites  are  at  present 
quarried  in  America  only  in  Montgomery,  Saline,  Hot  Springs,  and 
Garland  counties,  in  Arkansas,  and  are  known  commercially  as  the 
Washita  (or  Ouachita,  as  the  name  is  properly  spelled)  and  Arkansas 
stones.  Both  varieties  are  nearly  pure  silica,  the  Ouachita  being 
often  of  a  yellowish  or  rusty  red  tint,  and  the  Arkansas  of  a  pure 
snow  whiteness,  the  latter  variety  being  also  the  hardest,  most  com- 
pact, and  highest  priced.  The  analyses  given  below  show  the  average 
composition  of  the  two  varieties: 


Constituents. 

Arkansas. 

Ouachita. 

SiO 

ALO,  . 

vvow 

O.2O 

yy-4y 

O.I  ^ 

Fe  O 

O  IO 

CaO  

O  IO 

o  04. 

MgO.. 

O.Os 

o  08 

K,O  . 

O.IO 

0.16 

Na,O  

O.IS 

O.IO 

H,6  .. 

O.IO 

O.  I  J. 

According  to  Griswold  stone  suitable  for  the  manufacture  of 
whetstones  occurs  in  Quantity  in  two  distinct  horizons  in  the  Arkansas 
novaculite  series  of  rocks,  both  of  which  are  now  being  worked. 
The  principal  quarries  are  in  the  massive  white  beds  of  the  Hot 
Springs  region,  the  material  being  mainly  of  the  fine,  compact  white 
Arkansas  type.  Within  a  limited  region,  northeast  of  Hot  Springs, 
the  stone  becomes  more  porous,  owing  in  part  to  the  existence  of  a 
larger  number  of  the  rhomboidal  cavities,  and  passes  over  to  the 
Ouschita  type. 

The  microscopic  structure  of  the  Arkansas  novaculite  is  shown 
in  Plate  XXXVII,  Fig.  i,  the  large  white  areas  being  angular  granules 
of  quartz. 

Owen  regarded  the  Arkansas  novaculites  as  belonging  to  the  age 
of  the  millstone  grit  formation;  that  is,  to  the  lower  part  of  the 


>  j — Quarry  in  Mica  Schist  used  in  making  Whetstones,  Pike  Manufacturing  Co. 


FIG.  2. — Quarry  in  Novaculite,  Arkansas,    Pike  Manufacturing  Co. 

PLATE  XXXVI. 

[Facing  page  406.] 


MISCELLANEOUS.  407 

Carboniferous,  and  considered  them  as  a  sandstone  metamorphosed 
and  freed  from  impurities  by  the  action  of  hot  alkaline  waters.  State 
Geologist  Branner,  however,  regards  the  finer  grade  of  novaculite 
as  a  metamorphosed  chert,  a  conclusion  more  in  accordance  with 
the  microscopic  structure  of  the  rock,  which  is  more  that  of  chalce- 
dony than  of  an  altered  sandstone.  Griswold,  on  the  other  hand, 
regards  the  novaculite  as  a  product  of  sedimentation  of  a  fine  siliceous 
silt,  and  of  Lower  Silurian  age,1  while  Rutley  2  considers  it  as  a 
product  of  chemical  replacement  by  silica  of  the  calcareous  material 
of  dolomite  or  dolomitic  limestone  beds. 

The  view  in  quarry  of  the  Pike  Manufacturing  Co.,  Plate  XXXVI, 
shows  the  novaculite  beds  dipping  60°  to  the  southeast,  the  bed  of 
good  stone  being  some  12  or  15  feet  in  thickness.  The  rock  is  every- 
where badly  jointed,  in  one  case  mentioned  by  Griswold  as  many  as 
six  different  systems  being  developed  in  a  single  quarry.  The  natural 
result  is  that  pieces  of  only  very  moderate  dimensions  are  obtainable 
even  under  the  most  'favorable  of  circumstances.  Fine  veins  of 
quartz  intersecting  the  rock  in  various  directions  increase  the  dif- 
ficulty of  getting  homogeneous  material  and  thereby  increase  the 
cost  of  the  output. 

The  Arkansas  stone  is  now  used  for  many  purposes  by  artisans 
of  all  classes,  by  wood-carvers,  jewelers,  manufacturer^  of  fine 
machinery  and  metal  work,  and  by  dentists  in  various  forms  of 
files  and  points.  Dentists  use  particularly  the  "  knife-blade,"  a 
very  thin,  broad  slip  of  stone,  triangular  in  section,  with  one  short 
side,  the  other  two  forming  a  thin  edge  as  they  come  together.  They 
are  used  for  filing  between  the  teeth.  Carvers  use  wedge-shaped,  flat, 
square,  triangular,  diamond -shaped,  rounded,  and  bevel-edged  files 
for  finishing  their  work.  Jewelers,  especially  manufacturing  jewel- 
ers and  watchmakers,  use  all  these  forms  of  files  and  also  points. 
These  last  are  sometimes  made  the  size  of  a  leadpencil,  having  a 
cone-shaped  end,  and  are  about  3  inches  long  and  }  inch  square, 
tapering  to  a  point.  They  are  used  chiefly  in  manufacturing  watches 
to  enlarge  jewel-holes. 

1  See  Whetstones  and  Novaculites,  by  L.  S.  Griswold,  Annual  Report  of  the  Geo- 
logical Survey  of  Arkansas,  III,  1892.     This  report  contains  a  very  full  discussion  of 
the  Arkansas  novaculite  in  all  its  bearings. 

2  Quarterly  Journal  of  the  Geological  Society  of  London,  I.,  1894,  p.  377. 


408 


THE  NON-METALLIC  MINERALS. 


Wheels  of  various  thicknesses  and  diameter  are  also  made  from 
Arkansas  stone.  Such  are  used  chiefly  by  jewelers  and  dentists. 
The  difficulty  of  obtaining  pieces  of  clear  stone  large  enough 
for  wheels  several  inches  in  diameter  makes  the  price  very  high, 
and  the  difficulty  of  cutting  out  a  circular  form  increases 
the  cost.  Wheels  are  quoted  at  from  $1.10  to  $2.20  an  inch  of 
diameter. 

Fragments  of  the  Arkansas  stone  are  saved  at  the  factories,  and 
now  and  then  sent  away  to  be  ground  for  polishing  powder.  In  the 
manufacture  of  this  powder  millstones  are  worn  out  so  rapidly  that 
the  process  is  rather  expensive,  but  as  waste  stone  is  utilized,  the 
powder  can  be  sold  by  the  barrel  at  10  cents  a  pound.  It  makes  a 
very  fine,  pure  white  powder  of  sharp  grit,  suitable  for  all  kinds  of 
polishing  work;  it  is  known  as  "  Arkansas  powder." 

The  so-called  Turkish  oilstone  from  Smyrna,  in  Asia  Minor,  is 
both  in  structure  and  abrasive  qualities  quite  similar  to  the  Arkansas 
novaculites.  It,  however,  is  of  a  drab  color  and  carries  an  appre- 
ciable amount  of  free  calcium  carbonate  and  other  impurities,  as 
shown  by  the  analysis  given  below,  as  quoted  by  Griswold: 

TURKEY-STONE. 


Constituents. 

Per  Cent. 

Silica  CSiO2)  .              

72  oo 

Alumina  (A12O3)  

•3      I? 

Lime  (CaO)  .  .             

I?,-}? 

Carbonic  acid  (CO2)  

10  33 

According  to  Renard,1  the  celebrated  Belgian  razor  hone  quarried 
at  Lierreux,  Sart,  Salm-Chateau,  Bihau,  and  Recht  is  a  damourite 
slate  containing  innumerable  garnets,  more  than  100,000  in  a  cubic 
millimeter.  Like  the  Ratisbon  hone,  this  occurs  in  the  form  of  thin, 
yellowish  bands,  some  6  centimeters  wide  (2§  inches)  in  a  blue-gray 
slate  (phyllade).  The  bands  are  essentially  parallel  with  one 
another  and  with  the  grain  of  the  slate,  into  which  they  at  times 
gradually  merge.  The  chemical  composition  of  a  sample  from 
Recht  is  given  on  the  next  page.  The  microscopic  structure  of  the 
stone  as  described  and  figured  by  Renard  is  essentially  the  same 
as  that  of  the  Ratisbon  stone  in  the  collections  of  the  U.  S.  National 

1  Memoires  Couronnes  et  Memoircs  des  Savants  Etrangers  de  L' Academic  Royal 
des  Sciences,  etc.,  Belgique,  1878,  pp.  1-44. 


FIG.  i. 


^  'V 


•       :.-••  <v*  '   -W.*  '  <& 

•*     .       *  ,«  ^  '       '     * 

*  <n  r       \-«      ..s^  ^      -  *<-    ',       ,*%$>£\ 

^     *  -5    *       -  *"-'.*.  "  V^"*      «     > 


ff  %X-^W^^T' 

*i%^'^v.,^,-;:'^-- 
**.'V.*» 

FlG.    2. 

PLATE  XXXVII  . 
Microstructure  of  (i)  Arkansas  Novaculite  and  (2)  Ratisbon  Razor  Hone.     The  Dark 

Bodies  in  (2)  are  Garnets. 
The  enlargement  is  the  same  in  both  cases. 
[U.  S.  National  Museum.] 

[Facing  page  408.] 


MISCELLANEOUS. 

COMPOSITION  OF  BELGIAN  RAZOR  HONE. 


409 


Composition. 

Per  Cent. 

Silica  (SiO2)                          

46    < 

Titanic  oxide  (TiO2)         

I    17 

Alumina  (Al2Oo)                              .... 

22    C4 

Ferric  iron  (Fe2Oo)                     .      .    . 

I    OS 

Ferrous  iron  (FeO) 

o   71 

^Manganese  oxide  (M!nO) 

17    $4- 

Magnesia  (TvIgO) 

I    13 

Lime  (CaO) 

o  80 

Soda  (Na2O) 

O    3O 

Potash  (K2O)  

2.6o 

Water  (H2O)              

3.28 

Carbon  dioxide  (CO2)         

o  04 

Phosphoric  acid  (P2OK)                

o  16 

Sulphur  (S)                                             .    . 

o  18 

Organic  matter 

o  02 

Total 

00    II 

Museum  (See  Plate  XXXVIII,  Fig.  2),  and  the  stones  are  practi- 
cally identical  in  color  and  texture  as  well. 

The  cutting  property  of  the  stone  would  appear  to  be  due  to 
the  presence  of  the  small  garnets  above  noted. 

The  so-called  holystone  is  but  a  fine,  close-grained  sandstone 
of  the  same  nature  of  that  used  in  grind  and  whet  stones.  The 
greater  part  of  those  made  in  this  country  are  from  the  Berea  sand- 
stone of  Ohio,  though  some  are  said  to  be  imported  from  Germany. 
They  are  used  mainly  on  shipboard. 

2.   MILLSTONES. 

The  use  of  stone  in  the  form  of  flat  circular  disks  for  grinding 
grain  has  fallen  away  greatly  since  the  introduction  of  the  steel- 
roller  process.  Nevertheless,  the  smaller  mills,  and  particularly  the 
"grist  mills"  of  country  districts,  are  still  utilizing  the  old-time  ma- 
terial. Two  types  of  stone  are  in  common  use  for  this  purpose, 
the  one  a  siliceous  conglomerate  of  quite  variable  structure,  and 
the  other  a  vesicular  chalcedonic  rock  commonly  known  as  buhr- 
stone. 

Material  of  the  first  mentioned  type  is  found  in  the  United  States 
near  Esopus  Creek  in  Oneida  county,  New  York,  the  beds  belonging 


4io  THE  NON-METALLIC  MINERALS. 

to  the  Oneida  conglomerate  division  of  the  Niagara  (Upper  Silurian) 
period.  The  rock  consists  of  rounded  and  subangular  pebbles  of 
quartz  sometimes  2  c.m.  in  diameter,  compactly  embedded  in  a  fine 
siliceous  matrix  forming  an  exceedingly  tough  and  hard  mass  with  at 
the  same  time  a  sufficiently  sharp  grit  to  make  it  available  for  grind- 
ing purposes.  The  celebrated  German  millstone  from  Zittau  is  of 
a  somewhat  similar  nature,  though  the  large  quartz  pebbles  are 
in  this  case  embedded  in  a  more  sandy  matrix.  Buhrstone,  as  is 
noted  above,  is  a  chalcedonic  cellular  rock  commonly  regarded  as  a 
silicious  replacement  of  limestone,  and  containing  numerous  casts  of 
shells,  and  other  cavities.  The  rock  is  very  tough,  breaking  with  a 
sharp  splintery  fracture.  It  is  admirably  adapted  for  grinding 
grain,  and  has  been  so  used  from  a  very  early  period.  That  best 
known  comes  from  Tertiary  beds  near  Paris,  in  France.  A  good 
grade  of  material  of  similar  nature  is  stated  to  exist  in  large  quan- 
tities along  the  Savannah  River,  in  Georgia.  Though  occurring 
abundantly  it  is  not  found  in  a  continuous  stratum,  but  rather  in 
sporadic  masses  in  the  marl  beds. 

3.  PUMICE. 

The  material  to  which  the  name  pumice  is  commonly  given  is 
a  form  of  glassy  volcanic  rock,  which,  by  the  expansion  of  its  included 
moisture  while  in  a  molten  condition,  has  become,  like  a  well-raised 
loaf,  filled  with  air  cavities  or  vesicles.  The  cutting  or  abrasive 
quality  of  the  material  is  due  to  the  thin  partitions  of  glass  compos- 
ing the  walls  between  these  vesicles.  Any  variety  of  volcanic  rock, 
flowing  out  upon  the  surface  is  likely  to  assume  the  vesicular  con- 
dition known  as  pumiceous,  but  only  certain  acid  varieties  known  as 
liparites  seem  to  possess  just  the  right  degree  of  viscosity  and  amount 
of  moisture  to  produce  a  desirable  pumice,  and  in  this  rock  only  in 
exceptional  circumstances.  Almost  the  entire  commercial  supply  of 
pumice  is  now  brought  from  the  Lipari  Islands,  a  group  of  volcanoes 
north  of  Sicily,  in  the  Mediterranean  Sea,  where  it  is  dug  from  the 
loose  tuff  forming  the  cone  of  the  volcano.  The  material  is  usually 
brought  over  in  bulk  and  sold  in  small  pieces  in  the  drug  and  paint 
shops,  or  ground  and  bolted  to  various  degress  of  fineness  and  sold 
like  emery  and  other  abrasive  materials.  At  times  an  inferior  grade 


FIG.  i. — Bed  of  Pumice  Dust,  Kansas. 
[From  a  photograph.] 


FIG.  2. — Quarry  of  Quartz  Sand,  Ottawa,  Illinois. 

[From  a  photograph.] 

PLATE   XXXVIII. 

[Facing  page  410.] 


MISCELLANEOUS. 


411 


of  pumice  has  been  produced  from  volcanic  flows  near  Lake  Merced, 
in  California.  In  Harlan  County,  Nebraska,  and  adjacent  portions 
of  Kansas,  as  well  as  in  many  other  of  the  States  and  Territories 
farther  west,  have  been  found  extensive  beds  of  a  fine,  white  powder, 
which  was  first  shown  by  the  present  writer  l  to  be  pumiceous  dust, 
drifted  an  unknown  distance  by  wind  currents  and  finally  deposited 
in  the  still  waters  of  a  lake.  Through  a  mistaken  notion  regarding 
its  origin  this  material  was  first  described  in  Nebraska  as  geyserite. 
So  far  as  the  writer  is  aware,  these  natural  pumice  powders  have 
thus  far  been  exploited  only  for  polishing  purposes  and  as  a  cleansing 
or  scouring  agent  in  soap.  As  the  material  exists  in  almost  inex- 
haustible quantities,  it  would  seem  that  a  wider  scope  of  usefulness 
might  yet  be  discovered. 

The  analyses  given  below  show  (I)  the  composition  of  the  pumice 
dust  of  Harlan,  Orleans  County,  Nebraska,2  and  (II)  a  pumice  from 
Capo  di  Costagna,  Lipari  Islands: 


Constituents. 

I. 

II. 

Silica 

60.12 

73.70 

Alumina 

) 

12.27 

Iron  oxides 

1     17.64 

2.31 

o  86 

•*•£* 

o.6<c 

JVTagnfsia 

O  24. 

O.2Q 

Potash 

6  64. 

4.  73 

Soda 

I  60 

42  C 

Ignition 

4oc 

122 

Total     

100.24 

OQ.42 

The  Lipari  pumice,  in  commerce  is  classified  as  follows — 
grosse  (large  size),  correnti  (medium),  and  pezzani  (small);  the  large 
and  middle  sizes  are  subdivided  into  lisconi  (flat  and  rotondi  (round). 
The  lisconi  are  filamentous,  that  is,  the  vesicles  are  elongated  all 
in  one  direction,  and  break  less  easily  than  the  rotondi.  The 

1  See  On  Deposits  of  Volcanic  Dust  in  Southwestern  Nebraska  (Proceedings  U.  S. 
National  Museum,  VIII,  1885,  p.  99),  and  Notes  on  the  Composition  of  Certain  PUo- 
cene  Sandstones  from  Montana  and  Idaho  (American  Journal  of  Science,  XXXII, 
1886,  p.  199). 

2  Rocks,  Rock  weathering,   and  Soils,  p.  350. 


412  THE  NON-METALLIC  MINERALS. 

lisconi  and  rotondi  are  again  subdivided  into  white,  black,  and 
uncertain,  according  to  their  color. 

The  price,  it  is  stated,  varies  according  to  the  quality  from  50  to 
2,000  lire  the  ton.  The  common  price  for  the  assorted  is  350  to  500 
lire  the  ton.  As  much  as  5,000  tons  a  year  are  exported.  The  best 
pumice  is  that  of  Campo  Bianco.  It  is  also  obtained  at  Perera,  but 
it  is  in  small  quantity  and  was  produced  at  the  eruption  of  the  Forgia 
Vecchia.  It  is  a  first  class  gray  pumice  and  fetches  from  600  to 
750  lire  the  ton,  and  does  not  so  easily  break  as  the  Campo  Bianco. 
Also  at  Vulcano  a  gray  pumice  is  found,  but  the  presence  of  included 
crystals  renders  it  useless  for  commercial  purposes.  At  Castagna  a 
commoner  pumice  is  obtained  called  Alessandrina,  of  which  brick- 
shaped  pieces  are  made  and  used  for  smoothing  oil-cloth.1 

According  to  the  Engineering  and  Alining  Journal 2  a  merchant- 
able pumice  has  recently  been  found  in  Miller  County,  Idaho,  but 
the  demands  for  material  of  this  nature  is  likely  to  be  lessened  by  the 
putting  upon  the  market  of  a  German  artificial  product.  In  1897 
some  1700  tons  of  pumice  were  mined  near  Black  Rock,  Millard 
County,  Utah. 

Ground  and  bolted  pumice  is  quoted  as  worth  from  $25  to  $35  a 
ton  according  to  quality. 

4.   ROTTENSTONE. 

The  name  rottenstone  has  been  given  to  the  residual  product  from 
the  decay  of  silico-aluminous  limestones.  Percolating  carbonated 
waters  remove  the  lime  carbonate  from  these  stones,  leaving  the 
insoluble  residue  behind  in  the  form  of  a  soft,  friable,  earthy  mass 
of  a  light  gray  or  brownish  color,  which  forms  a  cheap  and  fairly 
satisfactory  polisher  for  many  metals. 

The  chemical  compositon  of  rottenstone,  as  may  well  be  imagined 
from  what  has  been  said  regarding  its  method  of  origin,  is  quite 
variable,  though  alumina  is  always  the  predominating  constituent. 
Analyses  as  given,  are  of  doubtful  value;  they  show:  Alumina, 
80  to  85  per  cent;  silica,  4  to  15  per  cent;  5  to  10  per  cent  of  carbon, 

1  The  South  Italian  Volcanoes,  by  H.  J.  Johnston-Lavis,  Naples,  F.  Furchheim, 
1891,  pp.  67-71. 

2  Volume  LXIV,  July  24,  1897,  p.  91. 


MISCELLANEOUS:  413 

and  equal  amounts  of  iron  oxides  and  varying  small  quantities  of 
lime.     The  material  has  little  commercial  value. 


5.    MADSTONES. 

The  fallacy  of  the  madstone  dates  well  back  into  the  dark  ages, 
and,  strange  as  it  may  seem,  continues  down  to  the  present  day. 
Not  longer  ago  than  December,  1898,  the  Washington  newspapers 
chronicled  the  sale  for  $450  of  a  madstone  in  Loudoun  County, 
Virginia,  and  from  year  to  year  very  many  letters  are  received  by 
the  Smithsonian  authorities  making  inquiries  regarding  such,  or 
possibly  offering  one  for  sale  at  fabulous  prices. 

So  far  as  the  writer  is  able  to  learn,  either  from  literature  or  from 
personal  examination,  stones  of  this  class  are  almost  invariably  of  an 
aluminous  or  clayey  nature,  and  their  supposed  virtue  is  due  wholly 
to  their  avidity  for  moisture — their  capacity  for  absorption,  which 
causes  them  to  adhere  to  any  wet  surface,  as  the  tongue  or  to  a  wound, 
until  saturated,  when  they  will  drop  away.  It  should  not  be  neces- 
sary to  state,  at  this  late  day,  that  their  curative  powers  are  purely 
imaginary.  The  ancient  bezoar  stone,  used  in  extracting  or  expelling 
poisons,  consisted  of  a  calculus  or  concretion  found  in  the  intestines 
of  the  wild  goat  of  northern  India.1 

6.   MOLDING   SAND. 

For  the  purpose  of  making  molds  for  metallic  casts,  a  fine,  homo- 
geneous argillaceous  sand  is  commonly  employed. 

The  physical  qualities  which  go  to  make  up  a  molding  sand  con- 
sist, according  to  Nason,2  of  elasticity,  strength,  and  a  certain  degree 
of  fineness.  It  must  be  plastic  in  order  to  be  molded  around  the  pat- 
tern; it  must  have  sufficient  strength  to  stand  when  unsupported  by 
the  pattern,  and  to  resist  the  impact  of  the  molten  metal  when  poured 
into  the  mold.  Too  much  clay  and  iron  present  in  the  sand  will 


1  W  J  Hoffman,  Folk  Medicine  of  the  Pennsylvania  Germans,  Proceedings  of  the 
American  Philosophical  Society,  XXVI,  1889,  p.  337. 

3  Forty-seventh  Annual  Report  of  the  Regents  State  Museum  of  New  York,  1893, 
p.  469. 


414 


THE  NON-METALLIC  MINERALS. 


cause  the  mold  to  shrink  and  crack  under  the  intense  heat;  too  little 
will  cause  it  to  dry  and  crumple,  if  not  to  entirely  collapse. 

The  peculiar  virtues  of  molding  sand,  as  outlined  above,  are 
ascribed  to  the  fact  that  each  of  the  sand  grains  is  coated  with  a  thin 
film  of  clay. 

The  accompanying  table  will  serve  to  show  the  varying  chemical 
character  of  sands  thus  employed,  though,  according  to  authorities 
quoted  by  Crookes  and  Rohrig,1  the  quality  of  the  sand  for  mold- 
ing depends  less  on  its  chemical  composition  than  on  its  physical 
properties,  namely,  whether  the  grains  are  round,  angular,  scaly,  etc., 
and  whether  they  are  of  uniform  size.  The  adhesiveness  is  dependent 
not  alone  on  the  quantity  of  clay,  but  upon  the  angularity  of  the 
grains,  and  by  a  mixture  of  smaller  and  larger  grains.  Reinhardt 
states  that  to  the  naked  eye,  a  good  sand  should  consist  of  particles 
seemingly  uniform  in  size,  with  a  sharp  feel  to  the  touch.  When 
strewn  upon  dark  paper  it  should  show  no  dust,  and  when  moistened 
with  from  10  to  20  per  cent  of  water  it  must  be  capable  of  being  formed 
into  balls  without  becoming  pulpy  or  being  too  easily  crushed. 


Constituents. 

I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

VII. 

SiO2  

02.083 

QI-QO7 

02.013 

00.62=; 

7Q.O2 

86.68 

87.6 

OO  2^ 

A12O3  

c.4ic 

S.683 

q.Sqo 

6.667 

I3.72 

9.23 

7.7 

4  .IO 

Fe.jO3andFeO.. 
CaO  

2.498 
Traces 

2.177 

0.41? 

1.249 
Traces 

2.708 
Traces 

2.4O 

3-42 
O.Q6 

3-6 

O.O6 

5-51 
O.23 

MeO 

O  71 

K  O 

4  c8 

99.996 

100.182 

IOO.OI2 

IOO.OOO 

100.43 

100.29 

99.86 

100.09 

Of  the  above  No.  i  is  from  Charlottenburg,  Germany,  No.  II,  a 
sand  employed  for  bronze  castings  in  Paris  foundries;  No.  Ill,  sand 
from  Manchester,  England;  No.  IV,  from  near  Stromberg;  No.  V, 
from  Ilsenburg,  in  the  Hartz  Mountains;  No.  VI,  from  Sheffield, 
England;  No.  VII,  from  Birmingham,  England,  and  No.  VIII,  from 
Liineburg. 

The  sand  from  Ilsenburg,  the  composition  of  which  is  given  in 


1  A  Practical  Treatise  on  Metallurgy,  II,  p.  626. 


MISCELLANEOUS. 


415 


column  5,  is  stated  l  to  be  prepared  by  mixing  "common  argillaceous 
sand,  sand  found  in  alluvial  deposits,  and  sand  from  solid  sandstone." 
In  preparation  the  first  two  are  carefully  heated  to  dehydrate  the  clay 
and  then  mixed,  equal  proportions  of  each  with  the  same  amount  of 
sandstone.  The  mixture  is  then  ground  and  bolted,  the  product 
being  as  fine  as  flour  and  capable  or  receiving  the  most  delicate  im- 
pressions. 

According  to  D.  H.  Truesdale,2  the  four  essential  qualities  in 
molding  sand  are,  in  the  order  of  their  importance,  (i)  refractoriness, 
(2)  porosity,  (3)  fineness,  and  (4)  bond.  These  qualities  are  depend- 
ent mainly  upon  the  varying  properties  of  siliceous  sand  and  clay, 
the  refractory  nature  being  governed  by  the  absence  of  such  fluxing 
constituents  as  calcium  cabonate,  the  alkalies,  or  of  iron  oxides. 
Since  in  nature  it  is  not  always  possible  to  obtain  the  admixture  of 
just  the  right  proportion,  artificial  mixtures  are  often  resorted  to,  as 
mentioned  above.  Ferguson  gives 3  the  following  analyses  of 
molding  sand  in  actual  use  in  his  foundries : 


Constituents. 

No.  i,  Fine 
Sand  for 
Snap  Work. 

No.  2,  Medium 
Grade  for 
Medium  Class 
of  Work. 

No.  3,  Coarse 
Sand  for  Heavy 
Machine 
Castings. 

No.  4,  for  Heavy 
Machinery  in 
Dry-sand 
Molds. 

Silica 

81  co 

84.  86 

82  92 

7O  8l 

Alumina 

o  88 

7  O3 

8  21 

IO  OO 

Ferric  oxide    

3.14 

2.l8 

2.QO 

4-44 

Combined  water    

3.00 

2.  2O 

a.8< 

2.8o 

Calcium  carbonate    .  .  . 
Magnesia    

1.85 
o.6c 

1.  10 
0.08 

I.IO 

None. 

1.25 

088 

Potassium  

No  estimate. 

No  estimate. 

No  estimate. 

No  estimate 

Manganese  

Trace. 

Trace. 

Trace. 

Trace 

Organic  matter 

Trace 

Trace 

Trace 

Trace 

Total  

IOO.O2 

0.8.  ?c 

07.  08 

QQ  27 

Sands  containing  lime  or  alkalies,  that  is  those  containing  free 
calcite  or  feldspathic  granules,  are  sometimes  liable  to  fusion  in  the 
case  of  heavy  castings.  It  is  customary  in  such  cases  to  coat  the 
surface  of  the  mold  with  graphite. 

The  following  table,  from  a  recent  report  of  the  State  Geologist 

1  Percy's  Metallurgy,  1861,  p.  239. 

2  The  Iron  Trade  Review,  October,  1897,  p.  24. 

3  Iron  Age,  LX,  December,  1897,  p.  16. 


416 


THE  NON-METALLIC  MINERALS. 


ON.J  ONt>.,j   •rf     r*-     vot^^j  ON^J   w  ,j 

9JcnCg  ON  CO  4;  to  CO  OJ    O        VO      CO  to  4J  tOfljSOaj 

aad  spunoj  in 

X 

to  voO    vo  O 

OOvotoOOOOOHOON     vooor^<NO»sONOOsOO 

O    OO      M      COSO     t^MVOMt^.        ON        M    OO      ON    N    OO      CO   t^OO     M 

^3"  co  ^  ^  co  d    ^"  ^~  ^"  co      co      ^"  co  co  *"3"  co  ^"  CO  co  ^st" 

vo  cot^-<NMCO  MQNON 

Nvoco  COMCO'GQCOM  T)-Oco 

\OOsO  sOsOO'VosOO  OOsO 

of  cs   ci  «   «   « 

VOOO    O  OO  OO    **••  VO  ^     C4  vO        O 

ON^J-voONto'tf'ONr^oOoO      vo    so    ONTfsooO    ON  coso    ON 
ONQO    ON  ONSO    M   t^-sO   t^.  i^**    so      ^*so   t^*sO  so    ^"  ^"  ^"  ^" 

vo 
O_l_    OjOdJtOVOtovo      vo      vo  vosO    M    CO  O    O    vo  vo 

•''OtT3 

•<    M    j-j    co  c    **5  t^sO  OO       r^-      MMcocoOOoOOOco 

^^  M  MM  CiMM 

^"  SO         OO  co  vo  to  co  co 

ONOOdvocovoOvovo     O       Ovow    cosO    vo  vo  vo  vo 

OO   O   f^"  ON  M    M  oO   to  O  so     so      t**-  w    M    O    ^"  ON  04    c<    TJ- 

ONVOt^-ONM  MMCOCO        M  COP»MC» 

M    CO          to          vo  vo          co  '^f 

p  MvoOvoOvoOvoOO      vovoO    voOO  so    O    O   vo  ON 

M     M     O  CO  d     M          M*        MM  M 

M    vo  O    ^    vo  co  vo  O    O   vo     O      vo  vo  *3"  'O    to  O    O    O    ON 
M          w    M  MMMM       M        M    M    M    M    M 

vo  ON  I-»  M    r->.  vo  OO 

MMQ          OcoOOOvo     vo     Ovo^cot^OvoOco 

M  MWMM          M          MMdMMM  M 

CO  Tj-   <L>  ^  n     .^^  2     )£  ,^  n     n    M? 

°  .      .   c3    O 

O    toi         ONSO  so    d    vo 

"^  d CQ   M     M 

<s  co  a;  to 

n  00  OOOvovoOvovoO<->™ 

o-oo g 

M  ^-t>.MCococo»-i       cosO  iJ    vo  O    d    ^  co  ON 


CO 


vo 

OO 

O      •    O 
0 


00 
vooO 

o    •    -oooo 


°°.     g 

W     ^J 


°°         o  oo  o1?0. 

vo  ON  t>» 


O    O    vo 
^XlOOOOO^'      '  oQ*   O 

& 


ing 
ndi 


ral  fo 
sand 
g 


sand  No.  o,  finest  castings 
"  No.  2,machinery  cast 
stove-plate  sand 
lle  No.  i  for  brass 
No.  3  for  gener 
No.  8  for  core 
steel  moldin 


ldi 


m 
ld 


vy  castings 

or  ron  and  brass. 
eavy  foundry  wor 
olding  sand 
ng  sand  No.  3 
g  sand  for  steel  mo 


o 
rton 


Alba 

'  * 
Gree 


n 


orence 

Lumbe 
« 


sand  f 
for  h 
m 
g 


n, 
mboy 
oldi 
ldin 
d 


ld 
to 
A 


e  m 
ntre 
uth 
rsey  m 
lica  mol 
e  san 


i 

S    %  a  B  £  .y  c 
U    SUc^^U 


MISCELLANEOUS.  417 

of  New  Jersey,1  will  show  the  physical  condition  of  some  well-known 
molding  sands: 

Sands  suitable  for  ordinary  castings  are  widespread,  though  the 
finer  grades  are  often  brought  considerable  distances,  some  of  those 
used  in  bronze  casting  in  America  being  imported  from  Europe. 
In  the  United  States  the  beds  are  alluvial  deposits  of  slight  thickness. 
Large  areas  occur  in  New  York  State,  in  counties  extending  from  the 
Adirondacks  to  New  Jersey.  At  date  of  writing  a  very  considerable 
proportion  of  the  material  used  in  the  eastern  United  States  is  dug 
in  Selkirk,  Albany  County,  New  York,  and  central  and  southern 
New  Jersey. 

The  Selkirk  molding  sand  is  of  a  yellow-brown  color,  showing 
under  the  microscope  angular  and  irregular  rounded  particles  rarely 
more  than  0.25  mm.  in  diameter,  interspersed  with  finely  pulverulent 
matter  which  can  only  be  designated  as  clay.  The  yellow-brown 
color  of  the  sand  is  due  to  the  thin  film  of  iron  oxide  which  coats  the 
larger  granules.  When  this  film  is  removed  by  treatment  with  dilute 
hydrochloric  acid,  the  constituent  minerals  are  readily  recognized 
as  consisting  mainly  of  quartz  and  feldspar  fragments  (both  ortho- 
clase  and  a  plagioclase  variety),  occasional  granules  of  magnetic 
iron  oxide,  and  irregularly  outlined  scales  of  kaolin,  together  with 
dust-like  material  too  finely  comminuted  for  accurate  determination. 
Many  of  the  larger  granules  are  white  and  opaque,  being  presum- 
ably feldspar  in  transition  stages  toward  kaolin.  An  occasional  flake 
of  hornblende  is  present. 

The  sands  occur  in  beds  varying  from  6  inches  to  3  feet  or  even 
5  feet  in  thickness.  They  immediately  underlie  the  surface  soil  and 
overlie  coarser,  well-stratified  sand  beds  more  nearly  allied  to  quick- 
sands. 

In  gathering  the  sands  for  market,  a  section  of  land  i  or  2  rods 
in  width  is  stripped  of  its  overlying  soil  down  to  the  sand,  which  is 
then  dug  up  and  carried  away.  When  the  area  thus  exposed  is 
exhausted,  a  like  area  immediately  adjoining  is  stripped,  the  soil  from 
the  second  being  dumped  into  the  first  excavation.  By  this  method 


1  Ann.  Rept.  of  State  Geologist  of  New  Jersey,  1904,  pp.  187-244.     See  also  Ries 
and  Rosen,  On  Foundry  Sands,  Rept.  Geological  Survey  of  Michigan,  1907. 


41 8  THE   NON-METALLIC  MINERALS. 

the  field,  when  finally  stripped  of  its  molding  sand,  is  ready  again 
for  cultivation. 

It  is  estimated  that  a  bed  of  sand  6  inches  in  thickness  will  yield 
1,000  tons  an  acre.  The  royalty  paid  the  farmers  from  whose  land 
it  is  taken  varies  from  5  to  25  cents  a  ton.  Some  60,000  to  80,000 
tons  are  shipped  annually  from  Albany  County  alone. 

The  term  green-sand l  is  applied  to  the  argillaceous  molding 
sands  in  an  undried  state,  and  which  is  employed  in  its  native  state, 
new  and  damp.  The  term  dry  sand  is  used  in  contradistinction,  to 
indicate  a  sand  that  must  be  dried  by  heat  before  being  fit  for  use. 
The  dry  sand  is  stated  to  be  firmer  and  better  adapted  than  the 
green  for  molding  pipes,  columns,  shafts,  and  other  long  bodies  of 
cylindrical  form. 

In  England  good  molding  sands  are  obtained  from  the  Lower 
Mottled  Sands  of  the  Bunter  (Trias)  beds  and  from  those  of  the 
Thanet  (Lower  Eocene). 

BIBLIOGRAPHY 

WALTER  BAGSHAW.     On  the  Mechanical  Treatment  of  Molding  Sand. 

Institute  of  Mechanical  Engineering  Proceedings,  1891,  pp.  94-107. 
F.  L.  NASON.     Economic  Geology  of  Albany  County. 

N.  Y.  State  Geologist,  i3th  Ann.  Report,  1894,  pp.  263,  287. 
EDWIN  C.  ECKEL.     Molding  Sand:  Its  Uses,  Properties,  and  Occurrence. 

N.  Y.  State  Geologist,  2ist  Ann.  Report,  1903,  pp.  rgi-rgb. 
H.  B.  KUMMEL.     Report  upon  Some  Molding  Sands  of  New  Jersey. 

Geological  Survey  of  New  Jersey,  Ann.  Rept.  of  State  Geologist  for  the  year 
1904,  pp.  187-244. 
HEINRICH  RIES  and  F.  L.  GALLUP.     Report  on  the  Molding  Sands  of  Wisconsin. 

Wisconsin  Geol.  and  Nat.  Hist.  Survey,  Bulletin  No.  15,  1906,  pp.  197-247. 

7.    SAND   FOR   MORTARS   AND   CEMENTS. 

Enormous  quantities  of  siliceous  sand  are  annually  used  in  the 
preparation  of  mortar  for  plastering  and  bricklaying,  or  in  cements. 
As  a  rule  no  great  amount  of  discrimination  is  shown  in  the  selection 
of  the  material,  the  matters  of  locality  and  cheapness  being  perhaps 
the  controlling  items.  It  by  no  means  follows,  however,  that  care 

1  This  must  not  be  confounded  with  the  Greensand  Marl,  or  Glauconitic  Sand 
used  for  fertilizing  purposes  (see  p.  420). 


MISCELLANEOUS.  4*9 

is  not  necessary  or  desirable.  It  is  stated  that  the  best  grades  are 
those  in  which  the  granules  present  a  considerable  diversity  of  size 
and  are  sharply  angular.  A  standard  adopted  for  use  in  construc- 
tion on  one  of  the  leading  railroads  demanded  that  54  per  cent 
should  pass  a  24-mesh  sieve,  and  u  per  cent  a  5o-mesh.  Clay  in 
amounts  as  high  as  12  per  cent  is  not  in  all  cases  objectionable. 

The  sources  of  such  sand  are  almost  infinite.  River  beds,  sea 
beaches,  and  sand  banks  wherever  found  are  the  common  resorts. 

8.    SAND    FOR   GLASS   MAKING. 

Quartz  sand  is  extensively  used  in  glass  making.  For  this 
purpose  a  fairly  pure  quartz  sand  is  needed,  though  naturally  the 
common  grades  of  bottle  glass  demand  a  much  less  pure  material 
than  do  the  higher  grades  of  flint,  or  plate  glass.  It  is  stated  1  that, 
aside  from  purity,  the  matter  of  size  and  shape  of  the  individual 
sand  grains  are  matters  of  primary  importance.  By  some  it  is 
contended  that  in  the  best  grades  the  grains  are  sharply  angular, 
rather  than  rounded.  Uniformity,  and  in  sizes  varying  from  0.15 
mm.  to  0.60  mm.,  seem  most  desirable.  Sands  containing  a  majority 
of  the  grains  less  than  0.136  mm.  in  diameter  (i.e.,  passing  a  120- 
mesh  sieve)  "  burn  out,"  and  produce  less  glass  per  unit  than  those 
which  are  coarser.  The  finer  grains  have  a  tendency  to  settle  to  the 
bottom  of  the  batch,  thus  preventing  a  homogeneous  mixture.  Sand 
in  which  the  grains  are  more  than  0.64  mm.  in  diameter  (3o-mesh) 
fuse  slowly,  thus  diminishing  the  daily  output  of  the  furnace  and 
incidentally  increasing  the  cost. 

The  chemical  composition  of  some  glass  sands  from  Southern 
New  Jersey  and  Pennsylvania,  and  others  in  use  by  manufacturers 
is  shown  in  the  table  on  page  420. 

The  impurities  in  these  sands  are  due  as  a  rule  to  mechanically 
entangled  bits  of  mica,  magnetite,  ilmenite,  or  rulite,  feldspar,  etc., 
which  can  often  be  largely  eliminated  by  washing. 

Large  quantities  of  sand  suitable  for  glass  making  are  attained 
either  from  beds  of  loose  sand  or  by  crushing  a  loosely  consolidated 

1  Annual  Report  State  Geologist  of  New  Jersey,  1906. 


420 


THE  NON-METALLIC  MINERALS. 


i 

2 

3 

4 

5 

6 

7 

8 

SiO2.. 
Fe203. 
A1203  . 
FiO,.. 

99.40 

0.0058 

0.2752 
o  0737 

99.62 
O.OO47 
0.142 

o  o=;4^ 

99.11 
0.0108 

0-355 
o  2213 

99.72 
O.OOI7 
O.I203 

o  0147 

98.94 
0.0036 
0.30 

99.21 
0.003 
0.30 

99-99 
Trace. 
0.008 

99-58 

0.21 

°-35° 

CaO.. 
MgO. 
Ignit.  . 

0.008 

O.OI2 

o.  231 

O.OI 

0.005 
o.  162 

0.009 
0.023 

O    IO 

0.007 
0.008 
o  134 

0.40 
Trace. 

O    23 

0.2O 

Trace. 

O.2I 

>  0.002 

0.50 

Nos.  i  and  2  used  chiefly  for  window,  green,  and  amber  glass. 
No.  3  used  only  in  cheaper  grades  of  glass,  as  for  beer  bottles. 
No.  4  used  for  best  grades  of  flint  glass. 
Nos.  5  and  6  sands  used  by  the  Pittsburg  Plate  Glass  Co. 
Nos.  7  and  8  sands  used  by  the  American  Window  Glass  Co. 

sandstone  in  Illinois,  Indiana,  Maryland,  Massachusetts,  Missouri, 
New  Jersey,  New  York,  Ohio,  Pennsylvania,  and  West  Virginia. 
Doubtless  equally  good  sands  may  be  found  in  other  localities,  but 
the  cost  of  fuel  is  the  controlling  item  and  a  large  share  of  the 
furnaces  are  in  regions  of  cheap  fuel  or  with  peculiarly  favorable 
facilities  for  transportation  or  for  market.  The  price  varies  from 
$0.90  to  $1.50  a  ton. 

9.   GLAUCONITIC   SAND. 

The  names  greensand,  greensand  marl,  and  glauconitic  marl 
are  given  to  a  dull  greenish,  loosely  coherent  arenaceous  deposit, 
consisting  essentially  of  the  hydrous  silicate  of  iron  and  potassium, 
but  variously  contaminated  with  particles  of  quartz  and  siliceous 
minerals,  oxides  of  iron,  clay,  rock  fragments,  and  particles  of  shells. 
The  table  on  page  421  from  the  Annual  Report  of  the  State 
Geologist  of  New  Jersey  will  serve  to  show  the  varying  composition 
of  the  material. 

The  most  extensive  and  best-known  deposits  in  the  United  States 
are  included  in  what  are  known  as  the  Upper,  Middle,  and  Lower 
marl  beds  of  the  Cretaceous  formations  in  southeastern  New  Jersey, 
though  it  is  also  known  to  occur  in  beds  of  Eocene  age  in  Maryland, 
Virginia,  North  and  South  Carolina,  and  Alabama.  Though  appar- 
ently limited  to  beds  of  no  particular  age,  it  seems,  nevertheless, 
most  abundant,  both  in  America  and  in  Europe,  in  the  Mesozoic 
formations. 


MISCELLANEOUS. 


421 


CHEMICAL  COMPOSITION  OF  GLAUCONITIC  MARLS. 


Constituents. 

I. 

II. 

III. 

IV. 

V. 

VI. 

Phosphoric  acid  

I.  1C 

o.s8 

O.IO 

O.  C.O 

6.87 

3    73 

Sulphuric  acid  

1.28 

0.41 

o.  34 

3.12 

2    44 

Silica  and  sand  

34.ro 

AC  .CO 

"CI.  1C. 

47.  ^O 

44  68 

49  68 

Potash  

I    CA 

3.7Q 

7.08 

C,     2Q 

3    07 

4   08 

Lime  

2    c,2 

I.CI 

'O.4Q 

o  <6 

4  07 

414 

Magnesia  

21? 

2    2O 

2   O2 

2    7O 

2   OO 

O   47 

0-47 

Alumina  

e       * 

6  oo 

5    80 

8  23 

8  60 

6  04 

Oxide  of  iron  

31     ^O 

24    SO 

23    13 

2O    C,  2 

18  07 

28  71 

Water  

o*  ow 
18  80 

1C,    4O 

*    * 

6  67 

13    c.7 

8  63 

5C.4 

Totals. 

00   43 

00    l8 

OO    37 

oo  c.8 

OO    32 

oo  60 

Origin. — The  glauconitic  beds  are  believed  to  have  been  formed 
in  comparatively  shallow  waters  during  periods  of  slow  sedimentation 
along  coasts  receiving  debris  from  continental  slopes  and  of  a  nature 
such  as  would  result  from  the  breaking  down  of  feldspathic  rocks. 
In  New  Jersey  the  beds  vary  from  30  to  60  feet  in  thickness,  but 
the  glauconitic  layers  are  not  homogeneously  distributed  through- 
out. 

Uses. — The  material  is  mined  from  open  pits  and  used  locally 
as  a  fertilizer.  The  percentages  of  phosphoric  acid,  potash,  and 
lime  are  too  low  to  warrant  transportation  for  any  distance. 


10.    ROAD-MAKING   MATERIALS. 

Roadways  subject  to  any  considerable  amount  of  traffic  demand 
almost  invariably  some  sort  of  stone  bedding  to  prevent  their  becom- 
ing soft  or  badly  cut  up  and  rutted  by  wheels  and  hoofs  of  horses. 
Until  within  a  comparatively  few  years,  it  has  been  the  general  custom 
to  pave  the  streets  of  cities  and  towns  with  rectangular  blocks  of 
granite,  trap,  or  other  hard  rock,  forming  thus  the  well-known 
Belgian  block  and  Telford  pavements.  Such  are  set  in  regular 
rows  and  the  interspaces  filled  with  sand  and  sometimes  with  tar  or 
asphalt.  For  suburban  and  country  roads  a  pavement  of  broken 
stone,  the  invention  of  a  Mr.  L.  Macadam  about  1820,  and  known 


422  THE  NON-METALLIC  MINERALS, 

by  his  name,  is  at  present  the  most  extensively  used.  The  invention 
is  based  upon  the  property  possessed  by  freshly  broken  stone  of 
becoming  compacted  and  to  a  certain  degree  even  cemented  when 
subject  to  heavy  rolling  and  the  impact  of  wheels.  The  finer 
particles,  broken  away  by  the  action  of  the  wheels  and  hoofs  of 
animals,  fill  the  interstices  of  the  larger  pieces  and  gradually  bring 
about  an  induration,  forming  a  roadbed  hard,  smooth,  and  durable. 

Not  all  materials  are  equally  good  for  macadamizing  purposes. 
If  the  rock  is  too  hard  ordinary  travel  is  not  sufficient  to  produce 
the  desired  amount  of  fine  material,  and  satisfactory  cementation 
does  not  ensue.  If  too  soft  it  grinds  away  too  rapidly.  If  the 
material  is  decomposed,  it  does  not  become  sufficiently  indurated 
— refuses  to  set,  as  it  were. 

It  is  impossible  to  lay  down  other  than  the  most  general  rules 
for  the  selection  of  road  material,  since  rocks  of  the  same  kind,  or  at 
least  known  under  the  same  name,  vary  almost  as  much  in  different 
localities  in  their  physical  properties  as  do  the  different  kinds.  The 
following  very  general  rules  have  been  formulated : l 

The  granites  are  generally  brittle,  and  many  of  them  do  not  bind 
well,  but  there  are  a  great  many  which,  when  used  under  proper 
conditions,  make  excellent  roads.  The  felsites  are  usually  very  hard 
and  brittle,  and  many  have  excellent  binding  power,  some  varieties 
being  suitable  for  the  heaviest  macadam  traffic.  Limestones  gener- 
ally bind  well,  are  soft,  and  frequently  hydroscopic.  Quartzites  are 
almost  always  very  hard,  brittle,  and  have  very  low  binding  power. 
The  slates  are  usually  soft,  brittle,  and  lack  binding  power. 

Obviously  the  bulk  matter  of  any  roadbed  must  be  built  up  of 
materials  from  nearby  sources,  owing  to  cost  of  transportation.  For 
surfacing,  however,  materials  are  often  carried  long  distances.  For 
this  purpose  a  hard,  dense  rock,  such  as  the  finer  grades  of  trappean 
rocks,  are  now  most  generally  used. 

Macadam  is  laid  with  or  without  a  foundation  of  larger  stones.2 

1  L.  W,  Page.     The  Selection  of  Materials  for  Macadam  Roads,  Yearbook  Dept 
of  Agriculture,   1900. 

2  With    the    foundation    of    larger    stones    the    pavement    becomes    known    as 
the  Macadam-Telford  pavement 


MISCELLANEOUS.  423 

When  such  is  used,  a  thickness  of  from  6  to  1 2  inches  is  recommended 
and  over  this  is  laid  from  4  to  6  inches  of  the  broken  stone  or  "  metal." 

"  Taking  all  points  into  consideration,  it  is  probable  that  the 
best  size  for  macadam,  for  hard  and  tough  stones,  such  as  basalt, 
close-grained  granite,  syenite,  gneiss,  and  the  hardest  of  primary 
crystallized  rocks,  is  from  ij  to  ij  inches  cube,  according  to  their 
respective  toughness  and  hardness,  while  stones  of  medium  quality 
ought  to  be  broken  to  gage  of  from  ij  to  2\  inches,  and  the  softer 
kinds  of  stone  might  vary  between  the  limits  of  2  and  2 \  or  2  j  inches, 
but  the  latter  is  a  size  which  should  seldom  be  specified." 

On  roads  for  light  driving  it  is  customary  to  place  a  final  surfacing 
of  smaller  stone,  such  as  will  pass  a  i-inch  mesh. 

u  Considerable  importance  is  attached  to  the  manner  in  which 
the  macadam  is  prepared  for  use.  Machine-broken  stone  is  not 
considered  of  the  same  value  as  that  broken  by  hand.  The  stones 
are  not  so  regular  a  size  and  shape,  and  there  is  a  greater  proportion 
of  inferior  stuff.  A  mechanical  crusher  is  apt  to  stun  the  material, 
and  does  not  leave  the  edges  so  sharp  for  binding  as  they  are  when 
the  stone  is  broken  with  a  small  hammer."  1 

The  cost  of  macadamized  roads  from  necessity  varies  almost  in- 
definitely. The  primary  factors  are  (i)  cost  of  labor,  (2)  accessibility 
of  materials,  and  (3)  character  of  country.  From  $2,000  to  $2,500 
a  mile  is  perhaps  an  average  figure  for  localities  where  materials  are 
available  close  at  hand. 

BIBLIOGRAPHY. 

Reports  of  the  Massachusetts  Highway  Commission,   1894,  and  others  up 
to  date. 
N.  S.  SHALER.     Geology  of  Road  Building  Stones  of  Mass. 

Sixteenth  Annual  Report,   U.  S.   Geol.   Survey,    1894-95,   pp.  277-341. 

F.  J.  H.  MERRILL.     Road  Materials  and  Road  Building. 

Bull.  N.  Y.  State  Museum,  Vol.  IV,  No.  17,  1897. 
L.  W.  PAGE.     The  Selection  of  Materials  for  Macadam  Roads. 
Yearbook  Dept.  of  Agriculture,  1900. 

G.  W.  TILLSON.     Street  Pavements  and  Paving  Material.     J.  Wiley  and  Sons,  1901. 

1  Circular  No.  12,  U.S.  Department  of  Agriculture,  Office  of  Road  Inquiry,  1896. 


INDEX. 


Adobe,  235. 
Agalmatolite,  215,  2i£. 
Albertite,  383. 
Allanite,  204. 
Alloclasite,  27. 
Alum  Clay,  244. 
Aluminite,  355. 
Alum  Slate,  357. 
Alums,  The,  350. 
Alunite,  355. 
Alunogen,  352. 
Amber,  391. 

Amber  Occurrences,  392. 
Amblygonite,  309. 
Anhydrite,  56. 
Anthracite  Coal,  364. 
Apatite,  267. 

Apatite  Deposits  of  Canada,  274. 
Apatite,  Occurrences  of,  273. 
Apjohnite,  351. 
Arsenic,  22. 

Arsenic,  Bibliography  of,  24. 
Arsenic,  Occurrence  of,  22. 
Arsenic,  Uses  of,  24. 
Arsenical  Pyrites,  30. 
Arsenopyrite,  30. 
Asbestic,  194. 

Asbestos,  Bibliography  of,  197. 
Asbestos,  Composition  of,  186. 
Asbestos  Deposits  of  Arizona,  191. 
Asbestos  Deposits  of  Canada,  189. 
Asbestos  Deposits  of  Georgia,  188. 
Asbestos  Deposits  of  Maryland,  189. 
Asbestos  Deposits  of  Vermont,  191. 
Asbestos  Deposits  of  Virginia,  188. 
Asbestos,  Localities  of,  189. 
Asbestos  Mining  and   Preparation   of, 
193. 


Asbestos,    Occurrence   and   Origin  of, 

185. 

Asbestos,  Uses  of,  193. 
Asbestos,  Varieties  of,  183. 
Asbolite,  28. 

Asphalt,  Bibliography  of,  398. 
Asphaltic  Sandrock,  379. 
Asphaltum,  375. 
Asphalt,  Uses  of,  380. 
Astrakanite,  56. 

Barite,  Composition  of,  334. 

Barite,  Occurrence  of,  335. 

Barite,  Preparation  and  Uses,  336. 

Bat  Guano,  299. 

Bauxite,  Bibliography  of,  102. 

Bauxite,  Composition,  89. 

Bauxite,  Origin  and  Occurrence,  91. 

Bauxite,  Uses  of,  101. 

Bauxite  Deposits  of  Alabama,  97. 

Bauxite  Deposits  of  Arkansas,  94. 

Bauxite  Deposits  of  France,  92. 

Bauxite  Deposits  of  Georgia,  97. 

Bauxite  Deposits  of  Germany,  93. 

Bedded  Clays,.  230. 

Belgian  Razor  Hone,  408. 

Bentonite,  246. 

Bieberite,  29. 

Biotite,  178. 

Bischoffite,  56. 

Bitumens,  Bibliography  of,  398. 

Bitumens,  Classification  of,  368. 

Bitumens,  Origin  of,  369. 

Bitumens,  The,  367. 

Bituminous  Coal,  363. 

Black  Diamond,  2. 

Bog  Manganese,  124. 

Boracite,  56,  322. 

425 


426 


INDEX. 


Borate  of  Soda  (see  Borax),  322. 

Borate  of  Magnesia,  322. 

Borates,  Occurrences     and     Localities, 

321,  322. 
Borax,  322. 

Borax,  Mining  and  Manufacture,  328. 
Borax,     Occurrence     and     Localities, 

322. 

Boronatrocalcite,  322. 
Bort,  2. 

Braunite,  121,  122. 
Brickclays,  232. 
Brown  Coal,  362. 
Buhrstone,  68. 

Calcite,  135. 

Calcium  Carbonate,  135. 

Calc  Spar,  135. 

Calc  Spar,  Origin  and  Occurrence  of, 

135- 

Carbon,  i. 
Carbonado,  2. 
Carbonates,  135. 
Carbonite,  385. 
Carnallite,  56. 

Carnotite,  Composition  of,  332,  333. 
Carnotite,  Occurrence  of,  332. 
Carnotite,  Uses  of,  334. 
Celestite,  Composition  and  Occurrence, 

343- 

Celestite,  Uses,  344. 
Cement,  Bibliography  of,  160. 
Cement,  Hydraulic,  140. 
Cement,  Portland,  141. 
Cement,  Roman,  144. 
Cement,  Rosendale,  143. 
Cerite,  207. 

Chalk,  Composition  and  Uses,  146. 
Chalk,  Origin  and  Occurrence,  145. 
Chemawinite,  393. 
Chilian      Nitrate,     Composition     and 

Occurrence,  317. 
China  Clay,  227. 
Chromite,  114. 

Chromite,  Bibliography  of,  120. 
Chromite,  Composition  of,  115. 
Chromite  Deposits  of  California,  117. 
Chromite  Deposits  of  Canada,  116. 


Chromite  Deposits  of  Greece,  120. 

Chromite  Deposits  of  Maryland,  119. 

Chromite  Deposits  of  Newfoundland, 
118. 

Chromite  Deposits  of  North  Carolina, 
116. 

Chromite  Deposits  of  S.  Africa,  117. 

Chromite,  Domestic  Source  of,  117. 

Chromite,  Occurrences  and  Origin, 
116. 

Chromite,  Uses  of,  118. 

Clays,  Bibliography  of,  250. 

Clays,  Cause  of  Plasticity,  238. 

Clays,  Composition  of,  228,  229,  231, 
233-237,  245-249. 

Clays,  Kinds  and  Classification,  226. 

Clays,  Mineral  and  Chemical  Composi- 
tion, 224. 

Clays,  Origin  and  Occurrence,  221. 

Clays,  Properties  of,  236. 

Clays,  Testing  of,  240. 

Clays,  Uses,  241. 

Coals,  Bibliography  of,  366. 

Coals,  The,  359. 

Cobalt,  Bibliography  of,  30. 

Cobalt  Bloom,  28. 

Cobaltite,  25. 

Cobalt  Minerals,  25. 

Cobaltomenite,  29. 

Cobalt,  Uses  of,  30. 

Colcothar,  37. 

Colemanite,  322. 

Columbite  and  Tantalite,  255. 

Columbite,  Composition,  Occurrence 
and  Uses,  255. 

Copal,  394. 

Copperas,  37. 

Corundum,  23. 

Corundum  Deposits  of  Canada,  79. 

Corundum  Deposits  of  Georgia,  77. 

Corundum  Deposits  of  Montana,  78. 

Corundum  Deposits  of  North  Carolina, 

74- 

Corundum,  Occurrence  of,  74. 
Corundum,  Origin  of,  80. 
Crocus,  104. 
Cryolite,  Composition  and   Occurrence 

of,  65. 


INDEX. 


427 


Cryolite,  Uses  of,  66. 

Descloizite,  312. 

Diallogite,  159. 

Diamond,  i. 

Diamond,  Bibliography  of,  5. 

Diamond,  Origin  and  Occurrence  of,  2. 

Diamond,  Uses  of,  5. 

Diaspore,  103. 

Diatom  Earth,  Composition  of,  72. 

Diatom  Earth,  Occurrence  and  Origin, 

70. 

Diatom  Earth,  Uses  of,  72. 
Dolomite,  Composition  and  Uses,  152. 
Douglasite,  56. 

Elaterite,  382. 
Elements,  The,  i. 
Emery,  Bibliography  of,  88,  89. 
Emery,  Composition  of,  81. 
Emery  Deposits  of  Asia  Minor,  82. 
Emery  Deposits  of  Massachusetts,  84. 
Emery  Deposits  of  Naxos,  82,  83. 
Emery  Deposits  of  New  York,  86. 
Emery  Deposits  of  the  United  States,  84. 
Emery,  Sources  and  Uses,  87. 
Emery,  Turkish,  82. 
Epsomite,  Epsom  Salts,  348. 
Erythrite,  28. 

Feldspars,  Composition  of,  161. 

Feldspars,  Occurrence  of,  161. 

Feldspars,  Uses  of,  164. 

Feldspars,  Weathering  of,  161. 

Ferberite,  257,  260. 

Fire  Clay,  230,  242. 

Flint,  68. 

Fluorite,  Bibliography,  65. 

Fluorite,  Occurrence,  63. 

Fluorite,  Uses,  65. 

Franklinite,  2*1,  122. 

Fullers  Earth,  252. 

Fullers  Earth,  Composition  of,  254.. 

Fullers  Earth,  Localities  of,  252. 

Fullers  Earth,  Uses  of,  254. 

Gadolinite,  205. 

Garnets,  Occurrence  of,  198. 

Garnet,  Uses  of,  199. 


Gibbsite,  103. 

Gilsonite,  386. 

Glass  Sand,  419. 

Glauberite,  56,  347. 

Glauber  Salt,  344. 

Glaucodot,  27. 

Glauconitic  Sand,  420. 

Grahamite,  384. 

Graphite,  6. 

Graphite,  Bibliography  of,  13. 

Graphite,  Canadian,  n. 

Graphite,  East  Indian,  n. 

Graphite  in  the  United  States,  ir. 

Graphite  Moravian,  10. 

Graphite,  Mexican,  10. 

Graphite,  Occurrence  and  Origin  of,  6. 

Graphite,  Preparation  of,  12. 

Graphite,  Price  of,  13. 

Graphite,  Sources  of,  n. 

Graphite,  Uses  of,  12. 

Graphite,  World's  Production  of,  13. 

Grindstone,  Materials  for,  400. 

Guanos,  Composition  of,  295,  299. 

Guanos,  Origin  of,  273. 

Guanos,  Soluble  and  Leached,  294. 

Gum  Copal,  394. 

Gypsum,  Age  and  Mode  of  Occurrence, 

338. 

Gypsum,  Composition,  337. 
Gypsum,  Origin  of,  338. 
Gypsum,  Uses  of,  342. 
Halides,  The,  43. 
Halite,  Composition,  43,  44. 
Halite,  Mining  and  Manufacture  of,  56, 
Halite,  Origin  and  Occurrence,  44. 
Halite,  Uses  of,  62. 
Halotrichite,  351. 
Halotrichite,  Composition  of,  353. 
Halloysite,  228. 
Hausmanite,  121,  122. 
Heavy  Spar,  334. 
Holystone,  409. 
Hones,  Materials  for,  400. 
Hubnerite,  257,  262. 
Hydrargillite,  103. 
Hydraulic  Limes  and  Cements,  160. 
Hydrocarbon  Compound,  359. 
Hydraulic  Cement,  140. 


428 


INDEX. 


Iceland  Spar,  Origin   and   Occurrence, 

135- 

Ilmenite,  112. 
Indianaite,  230. 
Indian  Red,  104. 

Infusorial  Earth  (see  Diatom  Earth),  70. 
Iron  Pyrites,  32. 
Island  of  Trinidad,  Asphalt  of,  375. 

Jet,  362. 

Kainite,  56. 

Kalinite,  350. 

Kaolin,  221. 

Kaolins  derived  from  Feldspars,  222. 

Kerosene  Shale,  363. 

Kieserite,  56. 

Kimberlite,  2. 

Kimberly  Diamond  Mines,  3. 

Krugite,  56. 

Lapis-lazuli,  202. 

Lapis-lazuli,  Localities  and  Occurrence, 

206. 

Lapis-lazuli,  Uses  of,  203. 
Lazarite,  Composition  and  Occurrence, 

202. 

Leda  Clays,  233. 
Lepidolite,  178. 

Lepidolite,  Occurrence  and  Origin,  219. 
Lepidolite,  Uses  of,  222. 
Leucopyrite,  Occurrence  and  Uses,  31. 
Lignite,  362. 
Limes  and  Cements,  Bibliography   of, 

160. 

Limes,  Classification  of,  141. 
Limestones,  Kinds  and  Origin,  138. 
Limestone,  Lithographic,  147. 
Limestone,  Uses  of,  139. 
Linnaeite,  27. 

Lithographic  Limestone,  147. 
Lithographic    Limestone,    Composition 

of,  148. 
Lithographic  Limestone,  Localities  of, 

147- 

Lithophillite,  310. 

Lollingite,  Occurrence  and  Uses,  31. 
Loess,  236. 


Macadam,  Material  for,  422. 

Mad  stones,  413. 

Magnesite,  Composition  of,  153. 

Magnesite,  Localities  of,  154. 

Magnesite,  Origin  and  Occurrence,  154. 

Magnesite,  Price  of,  156. 

Magnesite,  Uses  of,  156. 

Magnetic  Pyrites,  38. 

Manganese  Deposits  of  Brazil,  127. 

Manganese  Deposits  of  Cuba,  127. 

Manganese  Deposits  of  New  Bruns- 
wick, 127. 

Manganese  Deposits  of  Virginia,  125. 

Manganese  Oxides,  Composition  of, 
121. 

Manganese  Oxides,  Occurrence  of,  125. 

Manganese  Oxides,  Origin  of,  124. 

Manganese  Oxides,  Uses  of,  129. 

Manganite,  121,  123. 

Manganosite,  121. 

Manjak,  387. 

Marbles,  Playing,  146. 

Marcasite,  32. 

Marsh  Gas,  372. 

Meerschaum  (see  Sepiolite),  218. 

Menace  an  ite,  112. 

Mendozite,  351. 

Mica,  Bibliography  of,  183. 

Mica,  Composition  of,  165. 

Mica  Deposits  of  Alabama,  172. 

Mica  Deposits  of  Canada,  175. 

Mica  Deposits  of  Colorado,  172. 

Mica  Deposits  of  Connecticut,  169. 

Mica  Deposits  of  Maine,  168. 

Mica  Deposits  of  Nevada,  174. 

Mica  Deposits  of  New  Hampshire,  168. 

Mica  Deposits  of  New  Mexico,   172. 

Mica  Deposits  of  North  Carolina,   169. 

Mica  Deposits  of  South  Dakota,  173. 

Mica  Deposits  of  Wyoming,  172. 

Mica,  Localities  of,  167. 

Mica,  Occurrence  of,  166. 

Mica,  Origin  of,  167. 

Mica,  The,  164. 

Mica,  Uses  of,  180. 

Millstones,  409. 

Mineral  Caoutchouc,  382. 

Mineral  Paint,  Composition  of,  105. 


INDEX. 


429 


Mineral  Phosphates,  Localities,  273. 

Mineral  Pitch,  375. 

Mineral  Water,  Classification,  131,  132. 

Mineral  Water,  Distribution,  133. 

Mineral  Water,  Production  of,  134. 

Mineral  Water,  Source  of,  133. 

Mineral  Water,  Uses  of,  133. 

Mineral  Wax,  388. 

Mirabilite,  Composition,  345,  346. 

Mirabilite,  Occurrence,  344. 

Mispickel,  30. 

Molding  Sand,  413. 

Molding  Sand,  Bibliography  of,  418. 

Molding  Sand,  Composition  of,    414, 

4i5- 

Molding  Sand,  Localities  of,  417. 
Molding  Sand,  Mechanical  Analysis  of, 

416. 

Molybdenite,  39. 
Molybdenite,  Occurrence  of,  40. 
Molybdenite,  Uses  of,  41. 
Monazite,  302. 

Monazite,  Bibliography  of,  308. 
Monazite,  Composition  of,  304. 
Monazite,  Localities  and  Occurrences, 

3°3- 

Monazite,  Methods  of  Extraction,  306. 
Monazite,  Occurrences  of,  304. 
Monazite,  Uses  of,  307. 
Muscovite,  168. 

Natron,  159. 

Natural  Coke,  385. 

Natural  Gas,  372. 

Niobates,  Tantalates   and  Tungstates, 

255. 

Niter,  315. 

Nitrates,  Bibliography  of,  321. 
Nitrates,  Composition  of,  317. 
Nitrates,  Origin  of,  319. 
Nitrates,  Uses,  321. 
Nitrates,  The,  315. 
Nitro-Calcite,  318. 
Nitrous  Earth,  Composition  of,  319. 
Novaculite,  406,  407. 

Ocher,  104. 

Ochers,  Artificial,  Production  of,  104. 


Ochers,  Bibliography  of,  112. 
Ochers,  Composition  of,  104,  105. 
Ocher,  Origin  and  Mode  of  Occurrence, 

105,  106. 

Ocher,  Preparation  of,  109. 
Ocher,  Uses,  in. 
Orpiment,  Occurrence,  23. 
Orthite,  204. 
Oxides,  The,  67. 
Ozokerite,  388. 
Ozokerite,  Uses  of,  391. 

Paint,  Mineral,  103. 

Paper  Clay,  243. 

Paraffin,  Native,  388. 

Patronite,  41. 

Patronite,  Bibliography  of,  43. 

Patronite,  Occurrence  of,  42. 

Patronite,  Origin  of,  43. 

Patronite,  Uses  of,  43. 

Peat,  Origin  and  Composition,  360. 

Petalite,  200,  201. 

Petroleum,  Bibliography  of,  398. 

Petroleum,  Composition  of,  373. 

Petroleum,  Uses  of,  374. 

Phlogopite,  175. 

Phosphate  and  Vanadates,  266. 

Phosphates,  Bibliography  of,  301. 

Phosphates,  Composition  of,   268,  272, 

275~277>  294,  296-298. 
Phosphate  Deposits  of  Arkansas,  286. 
Phosphate  Deposits  of  Belgium,  291. 
Phosphate  Deposits  of  Canada,  273. 
Phosphate  Deposits  of  England,  288. 
'  Phosphate  Deposits  of  Florida,  280. 
Phosphate  Deposits  01  France,  290. 
Phosphate  Deposits  of  Germany,  291. 
Phosphate  Deposits  of  Idaho,  288. 
Phosphate  Deposits  of  Italy,  292. 
Phosphate  Deposits  of  Maltese  Islands, 

293- 

Phosphate  Deposits  of  Navassa,  296. 
Phosphate  Deposits  of  Nevada,  287. 
Phosphate  Deposits  of  North  Carolina, 

278. 

Phosphate  Deposits  of  Norway,  175. 
Phosphate  Deposits  of  Portugal-  277. 
Phosphate  Deposits  of  Redonda,  298. 


43° 


INDEX. 


Phosphate  Deposits  of  Russia,  292. 
Phosphate  Deposits  of  Sombrero,  296. 
Phosphate  Deposits  of  South  Carolina, 

280. 

Phosphate  Deposits  of  Spain,  276. 
Phosphate  Deposits  of  Tennessee,    282. 
Phosphate  Deposits  of  Tunis,  292. 
Phosphate    Deposits  of  United   States, 

288. 
Phosphate    Deposits   of   West     Indies, 

296. 

Phosphate  Deposits  of  Wyoming,  288. 
Phosphates,  Nodular,  271. 
Phosphates,  Uses  of,  300. 
Phosphorite,  269. 
Phosphorite,  Occurrence  of,  276. 
Pickeringite,  351. 
Finite,  216. 
Pipe  Clay,  230. 

Pitchblende  (see  Uraninite),  330. 
Plaster  of  Paris,  342. 
Playing  Marbles,  146. 
Plumbago,  6. 
Polianite,  121,"  123. 
Polyhalite,  56. 
Portland  Cement,  141. 
Potassium  Nitrate,  315. 
Potter's  Clay,  230,  242. 
Psilomelane,  121,  123. 
Pumice,  410. 
Pumice  dust,  411. 
Pyrallolite,  208. 
Pyrite,  32. 

Pyrite,  Bibliography  of,  39. 
Pyrite,  Composition  of,  33. 
Pyrite  Deposits  of  New  York,  34. 
Pyrite  Deposits  of  Spain,  35. 
Pyrite  Deposits  of  Virginia,  34. 
Pyrite,  Occurrence  and  Origin,  33. 
Pyrite,  Uses  of,  36. 
Pyrolusite,  121,  123. 
Pyrophyllite,  216. 
Pyrophyllite,     Occurrence     and    Uses, 

217. 
Pyrrhotite,  38. 

Quartz,  Varieties  and  Uses,  67. 
Quicklime,  140. 


Rare  Earths,  Bibliography  of,  308. 

Rare  Earths,  Uses  of,  307. 

Razor  Hones,  408. 

Realgar,  Occurrences,  23. 

Reichardite,  56. 

Remingtonite,  29. 

Rensselaerite,  208. 

Resin,  391. 

Resins,  Bibliography  of,  398. 

Retinite,  393. 

Rhodochrosite,  159. 

Rhodonite,  207. 

Road-making  Materials,  421. 

Road  Materials,  Bibliography  of,  423. 

Rock  Phosphate,  268,  278. 

Rock  Phosphate,  Origin  and  Occurrence, 

268. 

Rock  Salt,  43. 
Rock  Soap,  244. 
Roman  Cement,  144. 
Roscoelite,  179. 
Roselite,  28. 
Rottenstone,  412. 
Rouge,  104. 

Rutile,  Bibliography  of,  114. 
Rutile,  Localities  of,  113. 
Rutile,  Mode  of  Occurrence,  113. 

Safflorite,  27. 

Salt,  Common  (see  Halite),  43. 

Salt  Deposits  of  California,  58. 

Salt  Deposits  of  Canada,  47. 

Salt  Deposits  of  Colorado  Desert,  57. 

Salt  Deposits  of  England,  53. 

Salt  Deposits  of  Germany,  54. 

Salt  Deposits  of  Great  Salt  Lake,  59. 

Salt  Deposits  of  Kansas,  50. 

Salt  Deposits  of  Kentucky,  51. 

Salt  Deposits  of  Louisiana,  50. 

Salt  Deposits  of  Michigan,  49. 

Salt  Deposits  of  New  York,  47. 

Salt  Deposits  of  Ohio,  49. 

Salt  Deposits  of  Ontario,  47. 

Salt  Deposits  of  Petite  Anse,  50,  57. 

Salt  Deposits  of  Poland,  54. 

Salt  Deposits  of  Stassfurth,  54. 

Salt  Deposits  of  Texas,  52. 

Salt  Deposits  of  Wielicka,  54,  62. 


INDEX. 


431 


Salt  Deposits  of  Virginia,  46. 

Samarskite,  256. 

Sand  for  Glass  Making,  419. 

Sand  for  Mortars  and  Cements,  418. 

Scheelite,  Occurrence  and  Uses,  263. 

Schonite,  56. 

Scotch  Hones,  405. 

Segers.  Cones,  241. 

Sepiolite,  Composition  of,  218. 

Siegenite,  27. 

Silica,  67. 

Silicates,  The,  161. 

Skutterudite,  27. 

Slip  Clays,  234. 

Smaltite,  26. 

Soapstone,  208. 

Soapstone,  Composition  of,  209. 

Soapstone  Deposits  of  Maryland,  213. 

Soapstone  Deposits  of  Massachusetts, 
213. 

Soapstone  Deposits  of  New  Hampshire, 
212. 

Soapstone  Deposits  of  North  Carolina, 
214. 

Soapstone  Deposits  of  Pennsylvania, 
213. 

Soapstone  Deposits  of  Vermont,  212. 

Soapstone  Deposits  of  Virginia,  213. 

Soapstone  Industry  of  China,  215. 

Soapstone,  Localities,  212. 

Soapstone,  Occurrence,  211. 

Soapstone,  Uses,  214. 

Soda  Lakes,  346. 

Soda  Niter,  315. 

Sodium  Nitrate,  Localities  of,  3 15 . 

Sphaerocobaltite,  28. 

Spodumene,  Composition  and  Occur- 
rence, 200. 

Spodumene,  Uses  of,  201. 

Stassfurtite,  322. 

Steatite,  208. 

Strontianite,  Occurrence  and  Uses,  158. 

Succinite,  391. 

Sulphates,  334. 

Sulphate  of  Iron,  from  Pyrite,  37. 

Sulphur,  14. 

Sulphur,  Bibliography  of,  22. 

Sulphur  Deposits  of  Japan,  20. 


Sulphur  Deposits  of  Louisiana,  16. 
Sulphur  Deposits  of  Nevada,  17. 
Sulphur  Deposits  of  Sicily,  19. 
Sulphur  Deposits  of  Texas,  19. 
Sulphur  Deposits  of  Utah,  19. 
Sulphur,  Extraction  and  Preparation  of, 

21. 

Sulphur,  Localities  of,  15. 
Sulphur,  Occurrence  and  Origin,  14. 
Sulphur,  Uses  of,  21. 
Sylvite,  44. 
Synchnodymite,  28. 

Tachydrite,  56. 

Talc,  208. 

Talc,  Occurrence  and  Origin,  209. 

Talc  and  Steatite,  Composition  of,  209. 

Talc  Deposits  of  New  York,  210. 

Talc  Deposits  of  North  Carolina,  211. 

Talc  Deposits  of  Virginia,  210. 

Talc,  Uses,  214. 

Terra  Alba,  343. 

Thenardite,  348. 

Tincal,  322. 

Titanic  Iron,  112. 

Torbernite,  307. 

Triphyllite,  310. 

Tripoli,  69. 

Trona,  159. 

Tschermigite,  350. 

Tungstates,  Bibliography  of,  265. 

Turkey  Oilstone,  408. 

Uintaite,  386. 

Ulexite,  322. 

Ultramarine,  202. 

Uranates,  330. 

Uraninite,  330. 

Uraninite,    Localities  and   Occurrence, 

330. 

Uraninite,  Uses,  332. 
Urao,  159. 

Vanadates,  Uses  of,  314. 
Vanadinite,  311. 

Vanadium  Mica  (see  Roscoelite),  179. 
Vanadium  Sulphide  (see  Patronite),  41. 
Vitriol  Stone,  Composition  of,  37. 


432 


INDEX. 


Wad,  122,  124. 

Water,  Mineral,  131. 

Water  of  Ayr  Stone,  405. 

Wavellite,  308. 

Welsbach  Light,  308. 

Whetstones,  Materials  for,  400. 

Witherite,  Localities,  Occurrences  and 

Uses,  157. 

Wolframite,  Bibliography  of,  265. 
Wolframite,  Composition  of,  257. 


Wolframite,    Hubnerite   and   Ferberite, 

257- 

Wolframite,  Occurrence  of,  257. 
Wolframite,  Uses  of,  264. 
Wurtzillite,  382. 

Yttrotantalite,  255. 

Zircon,  199. 
Zircon,  Uses  of,  298. 


mm 

•  '-,•"•   '       -    sg 

Hi :/"..  m 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


AN  INITIAL  FINE  OF  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  5O  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


OEC    3     II 
DEC  21  1933 


FEB  12    1943 


APR   T    1943 


fl  1195: 


LD  21-100m-7,'33 


